Longevity Traits Research Articles

Genetic parameters for stayability of Holsteins in US organic herds

The objectives of this study were to estimate genetic parameters for stayability in US organic Holstein dairy cows and estimate genetic correlations with nationally evaluated traits of interest. Stayability is the binary trait for success or failure to remain in the herd until a given time point. We used birth, calving, and cull dates from 16 USDA certified organic farms recommended by industry personnel as herds maintaining individual cow records and using artificial insemination. Stayability at 5 time points was assigned based on the presence of a calving date for each parity up to 5 (STAY1 to STAY5). We also considered livebirth (vs. stillbirth), stayability from a successful first calving to second calving (STAY12), stayability from a successful second calving to third calving (STAY23), and stayability as a repeated measure encompassing STAY1 to STAY5. In total, 44,995 females were used in this study. Ninety-six percent were born alive and of these, 64% reached first parity. Animals with Holstein sires and no other identified breed for 3 generations on the maternal side were included. Heritabilities for stayability to each parity on the underlying scale were estimated using a threshold model with the fixed effect of herd and the random effects of animal and herd-year-season of birth. Genetic correlations were estimated among livebirth, STAY1, STAY12, and STAY23 with a 4-trait linear model with fixed herd-year-season of birth and random effects of animal, dam of the calf (livebirth), and herd calving date (STAY12 and STAY23). Heritabilities for stayability ranged from 0.07 to 0.15 and was 0.08 for the direct effect of livebirth and 0.06 for the maternal effect of livebirth. The repeatability for stayability was 0.60. Genetic correlations ranged from 0.11 between livebirth and STAY1 to 0.83 between STAY12 and STAY23. Excluding livebirth, stayability to all time points was significantly correlated with productive life and with cow livability. In general, stayability was positively associated with milk yield and negatively associated with fat percent and stillbirth. In conclusion, stayability in organic herds is heritable and positively associated with nationally evaluated longevity traits suggesting that improvement for stayability in organic herds can be achieved with current national evaluations for longevity.

Estimation of genetic parameters for predicted nitrogen use efficiency and losses in early lactation of Holstein cows

The objective of this study was to estimate genetic parameters of predicted N use efficiency (PNUE) and N losses (PNL) as proxies of N use and loss for Holstein cows. Furthermore, we have assessed approximate genetic correlations between PNUE, PNL, and dairy production, health, longevity, and conformation traits. These traits are considered important in many countries and are currently evaluated by the International Bull Evaluation Service (Interbull). The values of PNUE and PNL were obtained by using the combined milk mid-infrared (MIR) spectrum, parity, and milk yield-based prediction equations on test-day MIR records with days in milk (DIM) between 5 and 50 d. After editing, the final data set comprised 46,163 records of 21,462 cows from 154 farms in 5 countries. Each trait was divided into primiparous and multiparous (including second to fifth parity) groups. Genetic parameters and breeding values were estimated by using a multitrait (2-trait, 2-parity classes) repeatability model. Herd-year-season of calving, DIM, age of calving, and parity were used as fixed effects. Random effects were defined as parity (within-parity permanent environment), nongenetic cow (across-parity permanent environment), additive genetic animal, and residual effects. The estimated heritability of PNUE and PNL in the first and later parity were 0.13, 0.12, 0.14, and 0.13, and the repeatability values were 0.49, 0.40, 0.55, and 0.43, respectively. The estimated approximate genetic correlations between PNUE and PNL were negative and high (from -0.89 to -0.53), whereas the phenotypic correlations were also negative but relatively low (from -0.45 to -0.11). At a level of reliability of more than 0.30 for all novel traits, a total of 504 bulls born after 1995 had also publishable Interbull multiple-trait across-country estimated breeding values (EBV). The approximate genetic correlations between PNUE and the other 30 traits of interest, estimated as corrected correlations between EBV of bulls, ranged from -0.46 (udder depth) to 0.47 (milk yield). Obtained results showed the complex genetic relationship between efficiency, production, and other traits: for instance, more efficient cows seem to give more milk, which is linked to deeper udders, but seem to have lower health, fertility, and longevity. Additionally, the approximate genetic correlations between PNL, lower values representing less loss of N, and the 30 other traits, were from -0.32 (angularity) to 0.57 (direct calving ease). Even if further research is needed, our results provided preliminary evidence that the PNUE and PNL traits used as proxies could be included in genetic improvement programs in Holstein cows and could help their management.

Lifetime performance and longevity traits in Slovak Spotted dairy cows in dependence on feeding system

Article Details: Received: 2020-10-23 | Accepted: 2020-11-27 | Available online: 2021-01-31 https://doi.org/10.15414/afz.2021.24.mi-prap.114-117 The objective of this study was to analyse eight milk yield and longevity traits in dependence on feeding (grazing) system. Data of purebred Slovak Spotted dairy cows (35,812 heads) culled in the period between 2006 and 2019 were evaluated. Only herds those feeding (grazing) system was known were taken into account. Dairy cows were assigned to four groups: (1) heifers not grazed, cows not grazed (17,628 heads), (2) heifers grazed, cows not grazed (13,056 heads), (3) heifers not grazed, cows grazed (156 heads) and (4) heifers grazed, cows grazed (4,972 heads). The highest average 305-day milk yield (6,139.22 kg) and lifetime milk yield (18,606.78 kg) were found in animals of group (1). Contrariwise, longevity traits were found more favourable in animals of group (4). Their productive life was by 102.78 days longer and average parity was by 0.14 higher in comparison to group (1). The differences between groups were found significant. Keywords: milk yield, longevity, grazing, heifers, cows, Slovak Spotted cattle References Bujko, J. et al. (2020). Changes in production and reproduction traits in population of the Slovak spotted cattle. Acta fytotechnica et zootechnica, 23(3), 161–166, https://doi.org/10.15414/afz.2020.23.03.161-166. Canji, V. et al. (2008). Effect of conformation traits on longevity of cows of Slovak simmental breed . Slovak Journal of Animal Science, 41(2), 83–90. Fuerst–Waltl, B. et al. (2019). Mountain pasturing of rearing stock reduces the culling rist as dairy cows. Animal , 13(1), 209–212, doi: 10.1017/S1751731118001465. Krogmeier, D. et al. (2015). The effect of alpine pasturing of heifers on the longevity and on different yield traits of cows in Simmental and Brown Swiss cattle. Zuchtungskunde, 87(2), 107–119. Petrovic, M. et al. (2009). The effect of systematic factors on milk yield in Simmental cows over complete lactations. Biotechnology in Animal Husbandry , 25(1-2), 61–71, DOI: 10.2298/BAH0902061P . Ludovic-Toma, C. et al. (2017). Comparative study on production, reproduction and functional traits between Fleckvieh and Braunvieh cattle. Asian – Australasian Journal of Animal Sciences , 30(5), 666-671, doi: 10.5713/ajas.16.0588 . SAS Institute Inc.: SAS/STAT ® 9.2User’s Guide, Second Edition , Cary, NC USA, 2009. Strapak, P. et al. (2008). Effect of selected factors on the lenght of productive life of cows. S lovak Journal of Animal Science , 41(2), 77–82. Strapak, P. et al. (2010). Relation of the length of productive life and the body conformation traits in Slovak Simmental breed. Archives Animal Breeding , 53, 393–402. https://doi.org/10.5194/aab-53-393-2010

Genomic Correlations Between the Gaits of Young Horses Measured by Accelerometry and Functional Longevity in Jumping Competition.

Functional longevity is essential for the well-being of horses and the satisfaction of riders. Conventional selection using longevity breeding values calculated from competition results is not efficient because it takes too long to obtain reliable information. Therefore, the objective was to identify early criteria for selection. We assessed two types of early criteria: gait traits of young horses and QTLs. Thus, our aim was to estimate the genetic correlation between gait traits and longevity and to perform a genome-wide association study (GWAS) for longevity. Measurements of gaits by accelerometry were recorded on 1,477 show jumping horses that were 4 to 5 years old. Gait analysis provided 9 principal components describing trot, canter, and walk. Longevity estimated breeding values (EBVs) for stallions were calculated using a survival analysis of more than 900,000 years of performances by 179,448 show jumping horses born from 1981 onwards. Longevity was measured as the number of years spent in competition. Model included region and month of birth, age at first competition, year, and performance level. Longevity EBVs were deregressed to obtain weighted pseudo-performances for 1,968 stallions. Genomic data were available for 3,658 jumping horses. Seventy-eight percent of the horses measured for gaits and twenty-five percent of those measured for longevity were genotyped. A GWAS of longevity revealed no significant QTLs. Genetic parameters between each of the 9 principal components of the gait variables and longevity were evaluated with a bi-trait animal linear mixed model using single-step GBLUP analysis with the relationship matrix constructed from genomic data and genealogy (24,448 ancestors over four generations). The heritability of the gait traits varied from 0.11 to 0.44. The third principal component for trot (high lateral activity) and the first principal component for canter (high dorsoventral activity and low stride frequency) were moderately genetically correlated with higher longevity: rg = 0.38 (0.15) and 0.28 (0.13), respectively. Our study revealed that functional longevity is a polygenic trait with no major genes. We found new correlations between longevity and gait traits. Before using gait characteristics in a selection plan, these correlations need to be understood better at the biomechanical level.

Stress Mediating Genes in Aging, Health, and Longevity Traits: Effects of Multiple Interactions

Persistent stress of external or internal origin accelerates aging, increases risk of aging related health disorders, and shortens lifespan. Stressors activate stress response genes, and their products collectively influence traits. The variability of stressors and responses to them contribute to trait heterogeneity, which may cause the failure of clinical trials for drug candidates. The objectives of this paper are: to address the heterogeneity issue; to evaluate collective interaction effects of genetic factors on Alzheimer’s disease (AD) and longevity using HRS data; to identify differences and similarities in patterns of genetic interactions within two genders; and to compare AD related genetic interaction patterns in HRS and LOADFS data. To reach these objectives we: selected candidate genes from stress related pathways affecting AD/longevity; implemented logistic regression model with interaction term to evaluate effects of SNP-pairs on these traits for males and females; constructed the novel interaction polygenic risk scores for SNPs, which showed strong interaction potential, and evaluated effects of these scores on AD/longevity; and compared patterns of genetic interactions within the two genders and within two datasets. We found there were many genes involved in highly significant interactions that were the same and that were different within the two genders. The effects of interaction polygenic risk scores on AD were strong and highly statistically significant. These conclusions were confirmed in analyses of interaction effects on longevity trait using HRS data. Comparison of HRS to LOADFS data showed that many genes had strong interaction effects on AD in both data sets.

Using Random Regression Models to Genetically Evaluate Functional Longevity Traits in North American Angus Cattle.

Simple SummaryCattle longevity is usually defined as the duration of life of a cow from first calving to death. In addition to a longer lifespan, it is crucial that cows are productive throughout their lives. Incorporating optimal indicators of productive longevity in breeding schemes will directly improve the economic profitability of the beef cattle herd and long-term sustainability of the industry. Thus, the impact of different longevity indicators in the selection of North American Angus cattle was evaluated and optimal parameters were defined to perform the evaluations.This study aimed to propose novel longevity indicators by comparing genetic parameters for traditional (TL; i.e., the cow’s lifespan after the first calving) and functional (FL; i.e., how long the cow stayed in the herd while also calving; assuming no missing (FLa) or missing (FLb) records for unknown calving) longevity, considering different culling reasons (natural death, structural problems, disease, fertility, performance, and miscellaneous). Longevity definitions were evaluated from 2 to 15 years of age, using single- and multiple-trait Bayesian random regression models (RRM). The RRM fitting heterogenous residual variance and fourth order Legendre polynomials were considered as the optimal models for the majority of longevity indicators. The average heritability estimates over ages for FLb (from 0.08 to 0.25) were always higher than those for FLa (from 0.07 to 0.19), and higher or equal to the ones estimated for TL (from 0.07 to 0.23), considering the different culling reasons. The average genetic correlations estimated between ages were low to moderate (~0.40), for all longevity definitions and culling reasons. However, removing the extreme ages (i.e., 2 and >12 years) increased the average correlation between ages (from ~0.40 to >0.70). The genetic correlations estimated between culling reasons were low (0.12 and 0.20 on average, considering all ages and ages between 3 and 12 years old, respectively), indicating that longevity based on different culling reasons should be considered as different traits in the genetic evaluations. Higher average genetic correlations (estimated from 3 to 12 years old) were observed between TL and FLb (0.73) in comparison to TL and FLa (0.64), or FLa and FLb (0.65). Consequently, a higher average proportion of commonly-selected sires, for the top 1% sires, was also observed between TL and FLb (91.74%), compared to TL and FLa (59.68%), or FLa and FLb (61.01%). Higher prediction accuracies for the expected daughter performances (calculated based on the pedigree information) were obtained for FLb in comparison to TL and FLa. Our findings indicate that FLb is preferred for the genetic evaluation of longevity. In addition, it is recommended including multiple longevity traits based on different groups of culling reasons in a selection sub-index, as they are genetically-different traits. Genetic selection based on breeding values at the age of four years is expected to result in greater selection responses for increased longevity in North American Angus cattle.

Improving the accuracy of genomic evaluation for linear body measurement traits using single-step genomic best linear unbiased prediction in Hanwoo beef cattle

BackgroundRecently, there has been a growing interest in the genetic improvement of body measurement traits in farm animals. They are widely used as predictors of performance, longevity, and production traits, and it is worthwhile to investigate the prediction accuracies of genomic selection for these traits. In genomic prediction, the single-step genomic best linear unbiased prediction (ssGBLUP) method allows the inclusion of information from genotyped and non-genotyped relatives in the analysis. Hence, we aimed to compare the prediction accuracy obtained from a pedigree-based BLUP only on genotyped animals (PBLUP-G), a traditional pedigree-based BLUP (PBLUP), a genomic BLUP (GBLUP), and a single-step genomic BLUP (ssGBLUP) method for the following 10 body measurement traits at yearling age of Hanwoo cattle: body height (BH), body length (BL), chest depth (CD), chest girth (CG), chest width (CW), hip height (HH), hip width (HW), rump length (RL), rump width (RW), and thurl width (TW). The data set comprised 13,067 phenotypic records for body measurement traits and 1523 genotyped animals with 34,460 single-nucleotide polymorphisms. The accuracy for each trait and model was estimated only for genotyped animals using five-fold cross-validations.ResultsThe accuracies ranged from 0.02 to 0.19, 0.22 to 0.42, 0.21 to 0.44, and from 0.36 to 0.55 as assessed using the PBLUP-G, PBLUP, GBLUP, and ssGBLUP methods, respectively. The average predictive accuracies across traits were 0.13 for PBLUP-G, 0.34 for PBLUP, 0.33 for GBLUP, and 0.45 for ssGBLUP methods. Our results demonstrated that averaged across all traits, ssGBLUP outperformed PBLUP and GBLUP by 33 and 43%, respectively, in terms of prediction accuracy. Moreover, the least root of mean square error was obtained by ssGBLUP method.ConclusionsOur findings suggest that considering the ssGBLUP model may be a promising way to ensure acceptable accuracy of predictions for body measurement traits, especially for improving the prediction accuracy of selection candidates in ongoing Hanwoo breeding programs.

296 Awardee Talk: The Genetics of Sow Longevity

Abstract Sow longevity is a key productivity indicator trait that has real economic and welfare importance for commercial swine farms globally. The average parity at culling is 3.8 parities. Reports indicate that it takes 3 to 4 parities before a sow “pays for herself.” Research groups around the world have reported heritabilities estimates for sow longevity traits ranging from 0.05 to 0.35. Estimate differences result from the animal population under evaluation, the trait being evaluated, and the methodology employed to obtain the genetic parameter estimate. Because sow longevity is measured at the end of the sow’s productive life, indicator traits like age at first farrowing, leg conformation, and other traits are utilized in gilt selection programs. The genetic correlations between sow longevity and lifetime production traits range have been reported to range from 0.64 to 0.94, suggesting that selection will improve sow longevity. Genetic markers have been identified that affect both sow longevity and other indicator traits. Selection to improved sow longevity still requires phenotypes. Future technologies, e.g. CT scans, digital images, and automated disease detection, will provide additional phenotypes. Continued hardware, software, and molecular developments will improve selection accuracy for sow longevity traits and related traits. Research is needed to evaluate the impact that non-additive genetic effects have on sow longevity and other fitness-related traits. Sow longevity seems to be an ideal trait to employ genomic selection in order to make more rapid trait improvements because it is measured late in life, it is sex-limited, and the trait is not directly measured on nucleus animals. In conclusion, sow longevity and related traits have sufficient heritability and variation to improve through traditional and genomic enhanced selection methods. Selection programs employing effective genomic selection programs will be more effective in improving sow longevity trait and related traits and ultimately economical return.

Can Serum Nitrosoproteome Predict Longevity of Aged Women?

Aging is characterized by increase in reactive oxygen (ROS) and nitrogen (RNS) species, key factors of cardiac failure and disuse-induced muscle atrophy. This study focused on serum nitroproteome as a trait of longevity by adopting two complementary gel-based techniques: two-dimensional differential in gel electrophoresis (2-D DIGE) and Nitro-DIGE coupled with mass spectrometry of albumin-depleted serum of aged (A, n = 15) and centenarian (C, n = 15) versus young females (Y, n = 15). Results indicate spots differently expressed in A and C compared to Y and spots changed in A vs. C. Nitro-DIGE revealed nitrosated protein spots in A and C compared to Y and spots changed in A vs. C only (p-value < 0.01). Nitro-proteoforms of alpha-1-antitripsin (SERPINA1), alpha-1-antichimotripsin (SERPINA3), ceruloplasmin (CP), 13 proteoforms of haptoglobin (HP), and inactive glycosyltransferase 25 family member 3 (CERCAM) increased in A vs. Y and C. Conversely, nitrosation levels decreased in C vs. Y and A, for immunoglobulin light chain 1 (IGLC1), serotransferrin (TF), transthyretin (TTR), and vitamin D-binding protein (VDBP). Immunoblottings of alcohol dehydrogenase 5/S-nitrosoglutathione reductase (ADH5/GSNOR) and thioredoxin reductase 1 (TRXR1) indicated lower levels of ADH5 in A vs. Y and C, whereas TRXR1 decreased in A and C in comparison to Y. In conclusion, the study identified putative markers in C of healthy aging and high levels of ADH5/GSNOR that can sustain the denitrosylase activity, promoting longevity.

The association of clinical phenotypes to known AD/FTD genetic risk loci and their inter-relationship.

To elucidate how variants in genetic risk loci previously implicated in Alzheimer’s Disease (AD) and/or frontotemporal dementia (FTD) contribute to expression of disease phenotypes, a phenome-wide association study was performed in two waves. In the first wave, we explored clinical traits associated with thirteen genetic variants previously reported to be linked to disease risk using both the 23andMe and UKB cohorts. We tested 30 additional AD variants in UKB cohort only in the second wave. APOE variants defining ε2/ε3/ε4 alleles and rs646776 were identified to be significantly associated with metabolic/cardiovascular and longevity traits. APOE variants were also significantly associated with neurological traits. ABI3 variant rs28394864 was significantly associated with cardiovascular (e.g. (hypertension, ischemic heart disease, coronary atherosclerosis, angina) and immune-related trait asthma. Both APOE variants and CLU variant were significantly associated with nearsightedness. HLA- DRB1 variant was associated with diseases with immune-related traits. Additionally, variants from 10+ AD genes (BZRAP1-AS1, ADAMTS4, ADAM10, APH1B, SCIMP, ABI3, SPPL2A, ZNF232, GRN, CD2AP, and CD33) were associated with hematological measurements such as white blood cell (leukocyte) count, monocyte count, neutrophill count, platelet count, and/or mean platelet (thrombocyte) volume (an autoimmune disease biomarker). Many of these genes are expressed specifically in microglia. The associations of ABI3 variant with cardiovascular and immune-related traits are one of the novel findings from this study. Taken together, it is evidenced that at least some AD and FTD variants are associated with multiple clinical phenotypes and not just dementia. These findings were discussed in the context of causal relationship versus pleiotropy via Mendelian randomization analysis.

Fine mapping genetic variants associated with age at puberty and sow fertility using SowPro90 genotyping array.

Sow fertility traits, such as litter size and the number of lifetime parities produced (reproductive longevity), are economically important. Selection for these traits is difficult because they are lowly heritable and expressed late in life. Age at puberty (AP) is an early indicator of reproductive longevity. Here, we utilized a custom Affymetrix single-nucleotide polymorphisms (SNPs) array (SowPro90) enriched with positional candidate genetic variants for AP and a haplotype-based genome-wide association study to fine map the genetic sources associated with AP and other fertility traits in research (University of Nebraska-Lincoln [UNL]) and commercial sow populations. Five major quantitative trait loci (QTL) located on four Sus scrofa chromosomes (SSC2, SSC7, SSC14, and SSC18) were discovered for AP in the UNL population. Negative correlations (r = -0.96 to -0.10; P < 0.0001) were observed at each QTL between genomic estimated breeding values for AP and reproductive longevity measured as lifetime number of parities (LTNP). Some of the SNPs discovered in the major QTL regions for AP were located in candidate genes with fertility-associated gene ontologies (e.g., P2RX3, NR2F2, OAS1, and PTPN11). These SNPs showed significant (P < 0.05) or suggestive (P < 0.15) associations with AP, reproductive longevity, and litter size traits in the UNL population and litter size traits in the commercial sows. For example, in the UNL population, when the number of favorable alleles of an SNP located in the 3' untranslated region of PTPN11 (SSC14) increased, AP decreased (P < 0.0001), while LTNP increased (P < 0.10). Additionally, a suggestive difference in the observed NR2F2 isoforms usage was hypothesized to be the source of the QTL for puberty onset mapped on SSC7. It will be beneficial to further characterize these candidate SNPs and genes to understand their impact on protein sequence and function, gene expression, splicing process, and how these changes affect the phenotypic variation of fertility traits.

Age at first calving in UK Jersey cattle and its associations with first lactation 305-day milk yield, lifetime daily milk yield, calving interval and survival to second lactation

The association between age at fist calving (AFC) and production, fertility and survivability in Jersey heifers requires evaluation and comparison with published literature on Holstein heifers. Lactation records from 7256 pedigree Jersey heifers were grouped by AFC. Analysis comprised mixed effects multivariable regression modelling and binary logistic regression modelling. Increased lifetime daily yield (LDY) was significantly associated with a reduced AFC; calving UK Jersey heifers at 24 months or below is optimal. Heifers calving at 25-26 months had a significantly lower mean calving interval (391 days; 95 per cent CI 386 to 397) than those calving over 30 months (399; 95 per cent CI 394 to 405) (P=0.03). Heifers with an AFC over 30 months were less likely to survive to second lactation than those with an AFC 18-24 months. Spring calving heifers produced significantly less milk per day (9.87 kg; 95 per cent CI 9.64 to 10.1) than autumn (10.18; 95 per cent CI 9.94 to 10.41) or winter calvers (10.07; 95 per cent CI 9.84 to 10.3) (P≤0.01). Heifers that calved in the winter had a significantly shorter calving interval (389 days; 95 per cent CI 394 to 383) (P≤0.01) than heifers calved in other seasons. The impact of AFC on Jersey production, fertility and longevity traits shows a similar trend to that seen in the Holstein, potentially on a lesser scale.

Fire characteristics and environmental conditions shape plant communities via regeneration strategy

Climate change is altering disturbance regimes outside historical norms, which can impact biodiversity by selecting for plants with particular traits. The relative impact of disturbance characteristics on plant traits and community structure may be mediated by environmental gradients. We aimed to understand how wildfire impacted understory plant communities and plant regeneration strategies along gradients of environmental conditions and wildfire characteristics in boreal forests. We established 207 plots (60 m2) in recently burned stands and 133 plots in mature stands with no recent fire history in comparable gradients of stand type, site moisture (drainage) and soil organic layer (SOL) depth in two ecozones in Canada's Northwest Territories. At each plot, we recorded all vascular plant taxa in the understory and measured the regeneration strategy (seeder, resprouter, survivor) in burned plots, along with seedbed conditions (mineral soil and bryophyte cover). Dispersal, longevity and growth form traits were determined for each taxon. Fire characteristics measured included proportion of pre‐fire SOL combusted (fire severity), date of burn (fire seasonality) and pre‐fire stand age (time following fire). Results showed understory community composition was altered by fire. However, burned and mature stands had similar plant communities in wet sites with deep SOL. In the burned plots, regeneration strategies were determined by fire severity, drainage and pre‐ and post‐fire SOL depth. Resprouters were more common in wet sites with deeper SOL and lower fire severity, while seeders were associated with drier sites with thinner SOL and greater fire severity. This led to drier burned stands being compositionally different from their mature counterparts and seedbed conditions were important. Our study highlights the importance of environment–wildfire interactions in shaping plant regeneration strategies and patterns of understory plant community structure across landscapes, and the overriding importance of SOL depth and site drainage in mediating fire severity, plant regeneration and community structure.

Genome-wide association studies identify 137 loci for DNA methylation biomarkers of aging

Biological ageing estimators derived from DNA methylation data are heritable and correlate with morbidity and mortality. We report 137 genome wide significant loci (113 novel) via meta-analyses of six DNA methylation-based (DNAm) biomarkers in 34,962 European-ancestries and 6,482 African American individuals. Several DNAm biomarkers exhibit strong genetic correlations with multiple health and lifestyle measures. Polygenic scores explained up to 4.2% of the variance and the score for a DNAm estimator of mortality risk, DNAmGrimAge, was associated with parental longevity, education, and adiposity-related traits. Overall, this study greatly advances our understanding of the genetic determinants of epigenetic ageing processes in human blood.

Ecological connectivity with mangroves influences tropical seagrass population longevity and meadow traits within an island ecosystem

Seagrass meadows around the Andaman Sea are globally significant, but declining rapidly. Assessment of the existing seagrass population dynamics is essential to facilitate effective conservation measures. We studied population dynamics of the seagrass Thalassia hemprichii at 3 locations in the Andaman and Nicobar Islands in the Andaman Sea. At each location, 2 sites were assessed, one with mangroves (MG) and another without mangroves (WMG). Quadrat and corer sampling techniques were used to collect seagrass and sediment samples. Reconstruction techniques were used to derive population dynamics of T. hemprichii. Sand fractions dominated (&gt;90%) the T. hemprichii meadows, with silt comprising a higher percentage only at the MG sites. The density, biomass, productivity and horizontal meadow migration of T. hemprichii were higher at the MG sites. The number of leaves shoot-1, vertical rhizome (VR), VR internode length, number of VRs shoot-1 and vertical growth were higher at the WMG sites. T. hemprichii required less time to produce a single leaf at the MG sites than at the WMG sites. Plants associated with mangroves had 4 to 5 yr of longevity, with higher numbers of younger plants. Population growth rates were positive at all sites except at the WMG site of Burmanallah. Our results provide evidence that mangrove ecosystems have a positive impact on seagrass meadow traits and population dynamics. Therefore, it is crucial to focus on the ecological connectivity between seagrasses and associated coastal ecosystems, as it is pivotal to increase our understanding of the important link between coastal ecosystems and ecosystem functioning.

Gene expression and regulatory factors of the mechanistic target of rapamycin (mTOR) complex 1 predict mammalian longevity.

Species longevity varies significantly across animal species, but the underlying molecular mechanisms remain poorly understood. Recent studies and omics approaches suggest that phenotypic traits of longevity could converge in the mammalian target of rapamycin (mTOR) signalling pathway. The present study focuses on the comparative approach in heart tissue from 8 mammalian species with a ML ranging from 3.5 to 46 years. Gene expression, protein content, and concentration of regulatory metabolites of the mTOR complex 1 (mTORC1) were measured using droplet digital PCR, western blot, and mass spectrometry, respectively. Our results demonstrate (1) the existence of differences in species-specific gene expression and protein content of mTORC1, (2) that the achievement of a high longevity phenotype correlates with decreased and inhibited mTORC1, (3) a decreased content of mTORC1 activators in long-lived animals, and (4) that these differences are independent of phylogeny. Our findings, taken together, support an important role for mTORC1 downregulation in the evolution of long-lived mammals.Electronic supplementary materialThe online version of this article (10.1007/s11357-020-00210-3) contains supplementary material, which is available to authorized users.

Genetic markers associated with seed longevity and vitamin E in diverse Aus rice varieties

AbstractVitamin E is known to scavenge lipid peroxy radicals and has a purported role in preventing seed deterioration during storage. In our previous studies using 20 rice varieties from different variety groups, the specific ratio of vitamin E homologues rather than total vitamin E content was associated with seed longevity. To validate this result, we extended the experiment to a rice panel composed of 185 Aus (semi-wild rice) varieties. Seed longevity values were determined through storage experiments at 45°C and 10.9% seed moisture content (MC). Eight types of vitamin E homologues (α-, β-, γ- and δ-tocopherol/tocotrienol) were quantified by ultra-performance liquid chromatography. The theoretical initial viability in NED, Ki, was positively correlated with γ- and δ-tocopherols and negatively correlated with α-tocotrienol. The time for viability to fall to 50% during storage at elevated temperature and relative humidity, p50, was positively correlated with δ-tocopherol. The harvest MC was negatively correlated with all seed longevity traits. Taking this factor into account in a genome-wide association (GWA) analysis, we were able to correct false positives. A consistent major peak on chromosome 4 associated with −σ−1 was detected with a mixed linear analysis. Based on rice genome annotation and gene network ontology databases, we suggest that RNA modification, oxidation–reduction, protein–protein interactions and abscisic acid signal transduction play roles in seed longevity extension of Aus rice. Although major GWA regions were not overlapped across traits, three genetic markers, on chromosomes 1, 3 and 4, were associated with both δ-tocopherol and Ki and two markers on chromosome 1 and 8 were associated with both δ-tocopherol and p50.

Longevity Relatives Count score identifies heritable longevity carriers and suggests case improvement in genetic studies.

Loci associated with longevity are likely to harbor genes coding for key players of molecular pathways involved in a lifelong decreased mortality and decreased/compressed morbidity. However, identifying such loci is challenging. One of the most plausible reasons is the uncertainty in defining long‐lived cases with the heritable longevity trait among long‐living phenocopies. To avoid phenocopies, family selection scores have been constructed, but these have not yet been adopted as state of the art in longevity research. Here, we aim to identify individuals with the heritable longevity trait by using current insights and a novel family score based on these insights. We use a unique dataset connecting living study participants to their deceased ancestors covering 37,825 persons from 1,326 five‐generational families, living between 1788 and 2019. Our main finding suggests that longevity is transmitted for at least two subsequent generations only when at least 20% of all relatives are long‐lived. This proves the importance of family data to avoid phenocopies in genetic studies.

Stability analysis for seed longevity in landraces of sorghum [Sorghum bicolor (L.) Moench

Seed longevity in sorghum is a major determinant in seed production and germplasm preservation. Forty-six local landraces representing nine genetic races of sorghum were evaluated under accelerated aging and natural storage conditions to study the genotype-environment interactions and the stability of landraces for seed longevity. Genotype-environment interactions were highly significant indicating the influence of storage conditions on seed longevity. The stability of landraces was estimated using mean (xi), regression coefficient (bi) and regression deviation (S2di). Environmental indices for the seed longevity traits were high in E1 (fresh seed) followed by E2 (accelerated aged seeds), E3 (stored seeds for 12 months) and E4 (stored seeds for 24 months). Seven sorghum landraces viz., IC-345729 (Bicolor), IC-347571 (Caudatum), IC-347577 (Durra), IC-345244 (Durra), IC-415803 (Durra), IC-415822 (Durra bicolor) and IC-415829 (Guinea bicolor) were stable for seed longevity. These genotypes are therefore, recommended for use in further breeding to improve seed longevity in sorghum, which otherwise is generally poor.

Índices de selección para la mejora genética de vacas Siboney de Cuba

Se utilizaron los datos fenotípicos y genealógicos de vacas Siboney de Cuba (5/8 Hostein 3/8 Cebú) con partos de los años 1984 al 2016. El objetivo del estudio fue estimar los parámetros y valores genéticos (VG) de rasgos de producción, reproducción y longevidad, y construir índices de selección (IS) mediante el análisis de componentes principales (CP). Se estimaron los VG de 6 425 vacas para la producción de leche acumulada hasta los 305 días (VGL305), duración de la lactancia (VGDL), edad al primer parto (VGEp1), intervalo parto gestación (VGIPG), leche acumulada por vida (VGLTV) y vida productiva (VGVP). Las h2 para L305, DL, EP1, IPG, LTV y VP fueron de 0.16±0.01, 0.04±0.01, 0.04±0.01, 0.44±0.02, 0.05±0.01 y 0.01±0.01, respectivamente. La correlación genética entre L305 y DL fue de 0.36, entre EP1, IPG y LTV de 0.36, -0.42 y -0.36, y de VP con los otros rasgos fueron bajas (-0.24 a 0.11). El 70.8 % de la varianza total de los VG fue explicada por los CP1-3, siendo el CP1 el de mayor aporte (32.4 %). Los CP permitieron seleccionar por los CP1 y CP2, en lugar de seis VG. Se concluye que en el Siboney de Cuba es posible construir IS basados en los CP. La selección para VGL305 y VGDL podría realizarse mediante el índice PC1, otro IS (PC2) consideraría los VGIPG, VGEP1 y VGLTV; mientras que la VP podría mejorarse independientemente de los otros rasgos utilizando su VG.