High Inbreeding Coefficient Research Articles

Simplified Genomic Data Revealing the Decline of Aleuritopteris grevilleoides Population Accompanied by the Uplift of Dry-Hot Valley in Yunnan, China.

Understanding the evolutionary history of endangered species is crucial for identifying the main reasons for species endangerment in the past and predicting the changing trends and evolutionary directions of their future distribution. In order to study the impact of environmental changes caused by deep valley incision after the uplift of the Qinghai-Tibet Plateau on endangered species, we collected 23 samples belonging to four populations of Aleuritopteris grevilleoides, an endangered fern endemic to the dry-hot valleys (DHV) of Yunnan. Single-nucleotide variation sites (SNPs) were obtained by the genotyping-by-sequencing (GBS) method, and approximately 8085 SNP loci were identified. Through the reconstruction and analysis of genetic diversity, population structure, population dynamics, evolution time, and ancestral geographical distribution, combined with geological historical events such as the formation of dry-hot valleys, this study explores the formation history, current situation, reasons for endangerment and scientifically sound measures for the protection of A. grevilleoides. In our study, A. grevilleoides had low genetic diversity (Obs_Het = 0.16, Exp_Het = 0.32, Pi = 0.33) and a high inbreeding coefficient (Fis = 0.45). The differentiation events were 0.18 Mya, 0.16 Mya, and 0.11 Mya in the A. grevilleoides and may have been related to the formation of terraces within the dry-hot valleys. The history of population dynamics results shows that the diversion of the river resulted in a small amount of gene flow between the two clades, accompanied by a rapid increase in the population at 0.8 Mya. After that, the effective population sizes of A. grevilleoides began to contract continuously due to topographic changes resulting from the continuous expansion of dry-hot valleys. In conclusion, we found that the environmental changes caused by geological events might be the main reason for the changing population size of A. grevilleoides.

Genetic diversity and within-breed variation in three indigenous Ethiopian sheep based on whole-genome analysis

The objective of this work was to study genetic diversity by comparing whole genome sequence data of Rutana, Gumuz and Washera sheep found in Amhara and Benishanguel gumuz regional states of Ethiopia. We employed variant calling format tools version 0.1.15 to calculate some genetic diversity indices such as observed heterozygosity, expected heterozygosity, inbreeding coefficient, and nucleotide diversity. The results revealed that, observed heterozygosity ranged from 0.33 in Gumuz to 0.34 in Rutana and Washera sheep. Expected heterozygosity ranged from 0.37 in Rutana to 0.38 in Gumuz and Washera sheep. Expected heterozygosity was found to be higher than observed heterozygosity. Higher inbreeding coefficient (0.12) was recorded for Gumuz sheep compared to 0.09 of Rutana and Washera sheep. Mean nucleotide diversity values were 0.0029, 0.0030 and 0.0028 for Gumuz, Rutana and Washera sheep, respectively. Higher values of nucleotide diversity were recorded. Population structure analysis using principal component analysis revealed no clear separation between Gumuz, Rutana and Washera sheep populations with possibility of gene flow attributed to geographical location proximity. The smaller population size, closed breeding system, genetic drift and uncontrolled (non-random) mating might lead to higher rate of inbreeding in Gumuz, Rutana and Washera sheep, requiring timely intervention. This intervention helps to prevent inbreeding depression and extinction of these valuable breeds of sheep, which helps in sustaining the livelihood of sheep keepers in lowlands and highlands. Nevertheless, the whole-genome analysis revealed high within-breed variation. Uncovered areas of studies like mapping quantitative trait loci, identifying genes underpinning productivity traits such as carcass quantity and meat quality could be carried out on diversified sheep resources identified by the current study. Identifying the genomic regions and biological pathways that contribute to explaining variability in these traits is of great importance for selection purposes. Designing conservation-based within-breed sheep selective breeding programs are recommended considering economically important traits into account.

Whole-genome resequencing reveals genetic diversity and selection characteristics of dairy goat.

The dairy goat is one of the earliest dairy livestock species, which plays an important role in the economic development, especially for developing countries. With the development of agricultural civilization, dairy goats have been widely distributed across the world. However, few studies have been conducted on the specific characteristics of dairy goat. In this study, we collected the whole-genome data of 89 goat individuals by sequencing 48 goats and employing 41 publicly available goats, including five dairy goat breeds (Saanen, Nubian, Alpine, Toggenburg, and Guanzhong dairy goat; n = 24, 15, 11, 6, 6), and three goat breeds (Guishan goat, Longlin goat, Yunshang Black goat; n = 6, 15, 6). Through compared the genomes of dairy goat and non-dairy goat to analyze genetic diversity and selection characteristics of dairy goat. The results show that the eight goats could be divided into three subgroups of European, African, and Chinese indigenous goat populations, and we also found that Australian Nubian, Toggenburg, and Australian Alpine had the highest linkage disequilibrium, the lowest level of nucleotide diversity, and a higher inbreeding coefficient, indicating that they were strongly artificially selected. In addition, we identified several candidate genes related to the specificity of dairy goat, particularly genes associated with milk production traits (GHR, DGAT2, ELF5, GLYCAM1, ACSBG2, ACSS2), reproduction traits (TSHR, TSHB, PTGS2, ESR2), immunity traits (JAK1, POU2F2, LRRC66). Our results provide not only insights into the evolutionary history and breed characteristics of dairy goat, but also valuable information for the implementation and improvement of dairy goat cross breeding program.

Novel insights into the reproductive strategies of wild Chinese sturgeon (Acipenser sinensis) populations based on the kinship analysis

Understanding the reproductive strategy of an organism is important in conservation ecology as it directly affects the population performance under changing environmental conditions. Chinese sturgeon (Acipenser sinensis) are the largest anadromous fish in the Yangtze River, China. Currently, the species has only one spawning ground and has failed to spawn in recent years, leading it to the brink of extinction. To develop effective conservation measures, a further understanding of its reproductive strategy is needed. In our study, we conducted kinship analyses by using mitochondrial and microsatellite DNA data from 216 wild juveniles collected over nine years (2006−2013, 2015) to understand the mating system, breeding interval, effective number of breeding adults, and reproductive success. The results from these analyses suggested polygynandry, with some parents contributing up to eight half-sibling juvenile genotypes. Although the spawning ground was restricted to a limited area, genetic diversity was maintained at a relatively high level (observed heterozygosity from 0.698 to 0.787 and expected heterozygosity from 0.763 to 0.787) and inbreeding coefficients in each year-class ranged from −1% to 9% (low to modest detrimental effects on offspring). A parental inference analysis revealed that Chinese sturgeon have a breeding interval of 2–6 years, indicating that it has the potential to feed, accumulate nutrition in the ocean, and then migrate back to the Yangtze River for iteroparous reproduction. The annual effective number of breeders in the Yangtze River ranged from 14 to 161 during the study period, and it decreased by 62.1% from the 2011−2014 year-classes. This sharp population decline likely contributes to the reproduction failure. However, the ratios of effective to census population size (Ne/Nc) were all larger than 0.20 after the 2010 year-class, indicating relatively even reproductive success. Based on these results, a suggested approach to protect this species is to restock parent fish to increase the reproductive stock size and optimize the discharge of the Three Gorges Dam to reduce the unsuitable hydrological conditions and rehabilitate spawning ground habitats.

Using non-destructive sampling to evaluate the population genomic status of captive Brown Eared Pheasants

Evaluating the genetic status of threatened species is an essential task in conservation genetics. However, the genetic status of threatened species has been mostly evaluated through techniques that fail to estimate genetic diversity at the whole genomic level. Next generation sequencing can meet this demand, but high quality samples such as blood or muscle tissues are required. However, it is difficult to collect such samples from threatened species because sampling work may impact their health. Therefore, it is essential to design a workflow to evaluate the whole genomic status of threatened species using non-destructive sampling. Even though non-destructive sampling has been used in traditional barcoding technique, the barcoding technique cannot evaluate the whole genomic status. Brown Eared Pheasant (Crossoptilon mantchuricum) is an endangered species, with captive populations maintained in Taiyuan Zoo, China, and Europe. However, the genetic diversity, inbreeding pattern, and mutation load of these two populations are unclear. To uncover the genetic status of these two captive populations, we applied 2b-RAD technology to evaluate the genomic status of these populations using feathers as samples. The feathers could be collected by non-destructive sampling. The results indicate that the Taiyuan Zoo population has a lower genetic diversity and higher inbreeding coefficient than the European population. The Taiyuan Zoo population has lethal mutations when homozygous. The current project uses a non-destructive sampling technique to evaluate the whole genomic status of the two captive populations, providing a paradigm for conservation genetics, which will facilitate the development of conservation biology.

Analysis of Genetic Diversity and Population Structure of Cowpea (Vigna unguiculata (L.) Walp) Genotypes Using Single Nucleotide Polymorphism Markers.

Cowpea (Vigna unguiculata (L.) Walp) is an important legume crop with immense potential for nutritional and food security, income generation, and livestock feed in Sub-Saharan Africa. The crop is highly tolerant to heat and drought stresses which makes it an extremely important crop for improving resilience in crop production in the face of climate change. This study was carried out to assess the genetic diversity and population structure of 90 cowpea accessions using single nucleotide polymorphism (SNP) markers. Out of 11,940 SNPs used, 5864 SNPs were polymorphic and maintained for genome diversity analysis. Polymorphic information content (PIC) values ranged from 0.22 to 0.32 with a mean value of 0.27. The model-based Bayesian STRUCTURE analysis classified 90 cowpea accessions into four subpopulations at K = 4, while the distance-based cluster analysis grouped the accessions into three distinct clusters. The analysis of molecular variance (AMOVA) revealed that 59% and 69% of the total molecular variation was attributed to among individual variation for model-based and distance-based populations, respectively, and 18% was attributed to within individual variations. Furthermore, the low heterozygosity among cowpea accessions and the high inbreeding coefficient observed in this study suggests that the accessions reached an acceptable level of homozygosity. This study would serve as a reference for future selection and breeding programs of cowpea with desirable traits and systematic conservation of these plant genetic resources.

Methodological challenges in the genomic analysis of an endangered mammal population with low genetic diversity

Recently, populations of various species with very low genetic diversity have been discovered. Some of these persist in the long term, but others could face extinction due to accelerated loss of fitness. In this work, we characterize 45 individuals of one of these populations, belonging to the Iberian desman (Galemys pyrenaicus). For this, we used the ddRADseq technique, which generated 1421 SNPs. The heterozygosity values of the analyzed individuals were among the lowest recorded for mammals, ranging from 26 to 91 SNPs/Mb. Furthermore, the individuals from one of the localities, highly isolated due to strong barriers, presented extremely high inbreeding coefficients, with values above 0.7. Under this scenario of low genetic diversity and elevated inbreeding levels, some individuals appeared to be almost genetically identical. We used different methods and simulations to determine if genetic identification and parentage analysis were possible in this population. Only one of the methods, which does not assume population homogeneity, was able to identify all individuals correctly. Therefore, genetically impoverished populations pose a great methodological challenge for their genetic study. However, these populations are of primary scientific and conservation interest, so it is essential to characterize them genetically and improve genomic methodologies for their research.

Nghiên cứu di truyền loài Chò nâu (Dipterocarpus retusus) ở Phú Thọ phục vụ công tác bảo tồn và chọn giống

Dipterocarpus retusus is a valuable wood tree in the tropical forests of northern Vietnam, which is in danger of extinction due to habitat degradation and overexploitation. To date, this species has not been studied. In the present study, the genetic diversity and structure in four populations in Phu Tho province were investigated using microsatellites. A total of 23 alleles were identified, of which three were private alleles. The number of alleles per locus, effective alleles, observed and expected heterozygosity were 2.3, 1.5, 0.265, and 0.287, respectively. The lowest genetic diversity was found in the Chan Mong population, with an effectivealleles of 1.2, an observed heterozygosity of 0.153, and an expected heterozygosity of 0.16. A high inbreeding coefficient was found in Minh Phu (0.225). Genetic differentiation between populations was low (0.135) and gene flow was high (2.759). Habitat degradation can also decrease gene flow. Clustering analyses (Bayensia and Neighbor-joining) revealed three genetic clusters related to geographical distance and disturbed habitats. These results recommend the conservation and restoration of D. retusus in the future.

Extremely low level of genetic diversity in Gentiana yakushimensis, an endangered species in Yakushima Island, Japan

AbstractRare or endangered species largely contributing to global biodiversity are essential components of ecosystems. Because genetic diversity depends not only on apparent population size but also demographic processes, the conservation priority of endangered species based on population genetics needs to be assessed by comparison with common congeners and demographic events. In this study, we performed population genetic analysis for Gentiana yakushimensis Makino, a rare and endangered plant species with an isolated distribution on Yakushima Island, Japan. We performed comparison of genetic diversity with the congener (Gentiana triflora Pall. var. japonica [Kusn.] H.Hara), demographic inference, and bottleneck test based on genome‐wide single nucleotide polymorphisms. The result was that G. yakushimensis had an extremely low genetic diversity level and a high inbreeding coefficient level compared with those of the congener. The population of G. yakushimensis was estimated to experience an expansion during the Last Glacial Maximum and a recent bottleneck by the demographic inference and the bottleneck test. Therefore, the low level of genetic diversity of this species might have resulted from the impact of the recent bottleneck and the long‐term maintenance of a small population size. Due to the long lifespan of the genus Gentiana, the current level of genetic diversity probably does not reflect a large part of recent demographic events, which requires long‐term monitoring of changes in genetic diversity to identify the time lag between the reduction in apparent population size and genetic diversity as a future outlook.

Genetic Structure of Racing Pigeons (Columba livia) Kept in Poland Based on Microsatellite Markers.

Pigeons played a major role in communication before the invention of the telephone and the telegraph, as well as in wars, where they were used to carry information and orders over long distances. Currently, numerous sports competitions and races are held with their participation, and their breeding is demanding not only for breeders, but also for the birds themselves. Therefore, an analysis of the genetic structure of racing pigeons kept in Poland was undertaken on the basis of 16 microsatellite markers, as well as the evaluation of the microsatellite panel recommended by ISAG. For this purpose, Bayesian clustering, a dendrogram, and Principal Coordinate Analysis were conducted. In addition, statistical analysis was performed. Based on this research, it was observed that racing pigeons are genetically mixed, regardless of their place of origin. Moreover, genetic diversity was estimated at a relatively satisfactory level (Ho = 0.623, He = 0.684), and no alarmingly high inbreeding coefficient was observed (F = 0.088). Moreover, it was found that the panel recommended by ISAG can be successfully used in Poland for individual identification and parentage testing (PIC = 0.639, CE-1P = 0.9987233, CE-2P = 0.9999872, CE-PP = 0.99999999).

Changes in the genetic variability of the Furioso-North Star population between 1989 and 2019

The Furioso-North Star (FNS) is one of the indigenous Hungarian horse breeds, originated from Mezőhegyes Stud. The aim of this work was to analyze the pedigree diversity and inbreeding of the registered Hungarian Furioso-North Star population in two different time points: the first was the active population in 1989, the second was the active population in 2019. Pedigree data was analyzed using Endog 4.8 software. The pedigree completeness was calculated in three different ways. In the past 30 years the pedigrees became more complete. In the population 2019 were 5 horses with ancestor in the 40th generation. Only 17–17 animals covered the 50% of the genetic variability for the two population. The most important ancestor was Herod xx in both reference populations. The FNS breed has English Thoroughbred background, that might be the reason of having several horses form this breed in the database. There were six animals among the ten most important ancestors in both reference populations. The average inbreeding coefficient was 3.31 in 1989 and 4.22 in 2019. Animals with highest inbreeding coefficient were born from the mating of close relatives (typically father-daughter). The Bart Furioso III-84 Boglár had the highest inbreeding coefficient (0.299) in the population 2019.

Chromosome-level genome assembly for takin (Budorcas taxicolor) provides insights into its taxonomic status and genetic diversity.

The takin (Budorcas taxicolor) is one of the largest bovid herbivores in the subfamily Caprinae. The takin is at high risk of extinction, but its taxonomic status and genetic diversity remain unclear. In this study, we constructed the first reference genome of Bu. taxicolor using PacBio long High-Fidelity reads and Hi-C technology. The assembled genome is ~2.95Gb with a contig N50 of 68.05Mb, which were anchored onto 25+XY chromosomes. We found that the takin was more closely related to muskox than to other Caprinae species. Compared to the common ancestral karyotype of bovidae (2n=60), we found the takin (2n=52) experienced four chromosome fusions and one large translocation. Furthermore, we resequenced nine golden takins from the main distribution area, the Qinling Mountains, and identified 3.3million single nucleotide polymorphisms. The genetic diversity of takin was very low (θπ=0.00028 and heterozygosity=0.00038), among the lowest detected in domestic and wild mammals. Takin genomes showed a high inbreeding coefficient (FROH=0.217), suggesting severe inbreeding depression. The demographic history showed that the effective population size of takins declined significantly from ~100,000years ago. Our results provide valuable information for protection of takins and insights into their evolution.

Population genomic dynamics of mesopelagic lanternfishes Diaphus dumerilii, Lepidophanes guentheri, and Ceratoscopelus warmingii (Family: Myctophidae) in the Gulf of Mexico

Assessing the impacts of the Deepwater Horizon oil spill (DWHOS) on deep-sea fish assemblages of the Gulf of Mexico (GOM) has been hindered by an absence of baseline (pre-spill) data concerning the population genetic dynamics of these fishes. The lanternfishes (Myctophidae) are a speciose, yet understudied, taxonomic group, that comprise a significant portion of the global deep-sea biomass, making them integral members of meso- and bathy-pelagic food webs. Herein, we used a genomic approach (double digest restriction site associated DNA sequencing) to investigate the temporal genetic dynamics of three species of lanternfishes within the northern GOM in the region of the oil spill: Ceratoscopelus warmingii (N = 65, SNP = 1804), Diaphus dumerilii (N = 42, SNP = 2577), and Lepidophanes guentheri (N = 44, SNP = 3462). Fishes were sampled in 2011, and then again in 2015, and 2016, and genotyped using single nucleotide polymorphisms (SNP) markers. An additional 22 C. warmingii samples collected in 2014 from the western North Atlantic were used to assess genetic connectivity between these two regions. Overall, all three species were characterized by low levels of genetic diversity and high inbreeding coefficients, and within two of the three species (C. warmingii and L. guentheri), little (if any) evidence of population genetic structure was found within northern GOM waters. Conversely, significant intra-GOM genetic population structure was found for D. dumerilii, highlighting the need for a more robust population genetic survey of these fishes within the GOM to understand how populations of these fishes may respond to future environmental perturbations. In addition, significant genetic population structure was also found between sub-populations of C. warmingii from the northern GOM and western North Atlantic; with evidence of a mixture of two genetic populations co-occurring within the western North Atlantic. Given the potential for future environmental perturbations caused by expanding oil and gas extraction and climate change on GOM mesopelagic communities, rigorous population genetic assessments are required to understand the population dynamics of fishes and to safeguard the genetic diversity and resilience of this functionally important group of deep-sea fishes.

Genetic Diversity, Admixture and Analysis of Homozygous-by-Descent (HBD) Segments of Russian Wild Boar.

Simple SummaryThe wild boar is one of the most common wild animals. On the territory of Russia, there are two subspecies of the wild boar—European and Asian. At the beginning of the 20th century, the wild boar in the European part of Russia was practically exterminated. Later the population was restored by importing animals from other regions and by self-repopulation. The aim of our research was to assess the population structure of the Russian wild boar in comparison with the wild boar from other regions of the world and to determine the level of autozygosity, which allows us to determine the state of the population. We found traces of introgression of the Asian wild boar into the European one due to, migration of the wild boar in the population recovery process. Further analysis for genetic influx into Russian wild boar population identified four samples in which more than 10% of the genome belonged to domestic pigs. The Homozygous-by-Descent (HBD) Segments evaluation showed a low level of autozygosity in comparison with the aggregate sample of the European wild boar. Based on our genetic evaluation, we concluded that the population of the Russian wild boar of the European and Asian subspecies are characterized by a sufficient level of genetic diversity.The wild boar is the wild ancestor of the domestic pig and one of the most common species of ungulates. At the beginning of the 20th century, the wild boar was practically exterminated in the European part of Russia. In the period 1935–1988, 7705 boars were caught in various regions of the European part of Russia, the Far East, Ukraine, Belarus, Kyrgyzstan, Kazakhstan, Latvia, Lithuania, Estonia, Tajikistan and resettled in the territory of Russia. Asian and European wild boars dwell the territory of Russia. The aim of our research was to study the genetic diversity and structure of wild boar populations in different regions of Russia using genome-wide genotyping. We have determined the genetic distances, population structure, parameters of genetic diversity and significantly expanded our understanding of the genetic state of the Russian wild boar. For the first time, we calculated autozygosity of the wild boar of the European and Asian subspecies using Homozygous-by-Descent (HBD) Segments analysis, which is important in terms of population recovery. We also found evidence of hybridization between Russian wild boar and domestic pigs. A group of European wild boars showed introgression of the Asian boar into population. The mean level of the inbreeding coefficient in European wild boar was higher than in Asian wild boar, and combined groups of the European boar had higher inbreeding coefficient than Russian wild boars. These results obtained can be used in population management.

Sex-specific inbreeding depression: A meta-analysis.

Inbreeding depression, the reduced fitness of the offspring of related individuals, can affect males and females differently. Although a comprehensive theoretical framework describing the causes of sex‐specific inbreeding depression is lacking, empirical evidence suggests that often one sex tends to be more vulnerable than the other. However, the generality, direction, and degree of sex‐specific difference in inbreeding depression remains enigmatic as studies on this topic have reported conflicting results. Here, we conduct a meta‐analysis to test for sex‐specific differences in the magnitude of inbreeding depression. We synthetised 321 effect sizes of experimental studies across 47 species and found a small difference in inbreeding depression between the sexes: females suffered slightly higher inbreeding depression than males. Furthermore, a higher inbreeding coefficient was correlated with higher inbreeding depression. However, there was a large amount of heterogeneity that remained unexplained, even when considering different factors that could affect inbreeding between the sexes, such as sexual size dimorphism, heterogamety, the type of trait measured and whether animals were tested in a stressful environment. As such, we highlight the need to further explore inbreeding depression across different species to determine the occurrence and causes of sex differences to increase our understanding of the evolutionary consequences of sex‐specific inbreeding depression.

Agroecology Is Affecting Village Chicken Producers' Breeding Objective in Ethiopia.

This study assessed factors that determine village chicken producers' trait preferences in different agroecologies of Ethiopia. Three hundred and eighty village chicken producers were sampled for individual interviews. Data were analyzed using descriptive and inferential statistical techniques. Inbreeding coefficients of chicken populations in the three major agroecologies were estimated. In addition, the multivariate regression model was employed to evaluate the degree to which agroecological difference and socioeconomic and institutional factors impact village chicken producers' trait preferences. Egg and meat production for consumption and income generation were the three major village chicken production functions in the study. Plumage color and weight were ranked first for male and female chicken, respectively. Red plumage color (52.4%) was the primary choice followed by white color (24.5%). Agroecology and livestock holding (TLU) significantly (P < 0.05) affected farmers' preference toward economic traits, while land holding significantly (P < 0.05) affected reproductive traits. Distance to market significantly (P < 0.05) affected farmers' preference toward adaptive traits. The inbreeding coefficient of 0.25, 0.23, and 0.06 was recorded in low, mid, and highland agroecologies, respectively. The agroecological difference is affecting village chicken producers' breeding objective in Ethiopia. A higher inbreeding coefficient was observed in the low and mid agroecologies. Future breed improvement programs should give due consideration to village chicken producers' socioeconomic characteristics and agroecological differences.

Inbreeding status and implications for Amur tigers

AbstractInbreeding more likely occurs in small, isolated and endangered populations, and may influence the sustainable survival of a population. As the Amur tiger Panthera tigris altaica population in China experienced a severe decline in the 1990s, the recovering population may be prone to inbreeding and its potential impacts on population health. However, the inbreeding status has not been evaluated and relationships with health remain poorly understood in wild animals. Based on the genetic samples collected from the main Amur tiger habitats in China, this study analyzed the population inbreeding level, major histocompatibility complex polymorphism, parasitic infections and gut microbial structures and functions, and then explored the influence of inbreeding on these traits. Our results indicated that more than 50% of individual relationships were in cousin or half sibs, and 22.73% of individuals had moderate or high inbreeding coefficients. There was a significant positive correlation between the inbreeding level of an individual and the Toxocara cati parasitic load. Gut microbiota community structure and function were also impacted by inbreeding intensity. In conclusion, results indicate that the Amur tiger population in China has reached a moderate level of inbreeding and that there are direct interactions between inbreeding intensity and parasitic load and gut microbiota. This study thus provides an early warning on the Amur tiger population health and should prompt the construction of national and international ecological corridors and/or the re‐introduction of new individuals to relieve the evident inbreeding pressure.

Pan-India population genetics signifies the importance of habitat connectivity for wild Asian elephant conservation

Asian elephants are endangered while they have faced ~70% population decline in India in the last 60 years. Climate change projections indicate exacerbation of ongoing habitat loss (>40%) by 2070, potentially impacting genetic structure of wild elephants across India. Therefore, we provide consolidated baseline data on genetic diversity and structure of elephants across four eco-regions of India, i.e., north-western (NW), north-eastern (NE), east-central (ECI), and southern India (SI), to identify populations at greater risk of further divergence. We genotyped 169 faecal samples across 14 microsatellites with 90.0% overall success rate. The genetic diversity levels were moderate and varied between the eco-regions (HE =0.57–0.74). Allelic richness was higher in NE (3.73–3.78) and SI (3.62–3.71). We observed a high inbreeding coefficient in NE (FIS=0.55–0.58) compared to the other elephant populations, probably due to the presence of related individuals in our samples. Genetic differentiation between populations using FST statistics (FST=0.06–0.18) was significant. Bayesian and multivariate analyses identified three major genetic clusters in India – NW, NE, and combined ECI-SI, mostly consistent with their geographic distribution. We also observed an unexpected pattern of high genetic distance between adjacent populations. This fine-scale genetic structure suggests the presence of barriers (natural and anthropogenic) and complex social organisation. Additionally, incipient sub-structuring within NE and SI indicates potential genetic discontinuity. These results highlight the importance of maintaining genetic diversity, particularly of NE and ECI populations, by retaining habitat connectivity and ensuring gene flow for effective elephant conservation in India.

Genetic and Phenotypic Characterization of Domestic Geese (Anser anser) in Egypt.

Simple SummaryThe production of domestic geese in Egypt depends mainly on small-sized flocks reared by smallholder farmers in villages, and until now, there have been no intensive or commercial goose farms in Egypt. The objective of this study was to characterize three domestic Egyptian goose populations (Kafr El-Sheikh, Fayoum and Luxor) phenotypically and genetically in order to identify the populations with the highest diversity to establish a large base population with a broad variation. Phenotypic characterization of 402 domestic mature geese included morphological measurements such as head length, culmen length, bill width, tarsus length, sternum length and chest circumference. Genetic characterization of 173 individuals was performed based on mutations in the mitochondrial D-loop region and the genotyping of 12 microsatellite markers. The results showed low population differentiation based on morphological measurements and low genetic differentiation based on the two used genetic markers. The low differentiation between the three investigated goose populations implies their suitability for aggregation and formation of a large founder population with high genetic variation. The information from this study could be useful for further investigation in order to develop a convenient conservation program for this important species.The objectives of this study were to achieve phenotypic characterization of three domestic Egyptian goose populations collected from three different geographical zones (Kafr El-Sheikh, Fayoum and Luxor) and to perform genetic characterization of these three populations based on mtDNA D-loop and 12 microsatellite markers. The body measurements of 402 domestic mature geese belonging to these three governorates showed that the lengths of the head, culmen and tarsus and the live body weight varied significantly among the three studied Egyptian goose populations. After alignment of a 710-base-pair segment of the goose mtDNA control region, there was a single haplotype in the three Egyptian goose populations, indicating the same maternal origins. The genotyping of the 12 microsatellite markers showed low diversity indices, including average observed (NA) and effective (NE) number of alleles and observed (HO) and expected heterozygosity (HE) (3.333, 1.760, 0.277 and 0.352, respectively), and a high inbreeding coefficient (FIS = 0.203) across the three Egyptian goose populations. The high inbreeding and low genetic and morphological differentiation of Egyptian geese could be corrected by establishing a large base population through capturing small populations with the highest genetic variation. The findings of the current study can therefore serve as an initial guide to design further investigations for developing conservation programs of Egyptian geese genetic resources.

The Nero Lucano Pig Breed: Recovery and Variability.

Simple SummaryThe reduction of biodiversity determines the loss of species and breeds, with the consequent disappearance of production systems, knowledge, cultures and local traditions. The Nero Lucano pig is a native breed of Southern Italy (Basilicata region) recovered, starting from 2001, because of the high quality of its cured meat products. This study gives a picture of the low genetic variability of this breed. Knowledge of individual inbreeding levels allows for planning of interventions to reduce the negative effects of the low effective population size and, then, improve the efficiency of the actual recovery project.The Nero Lucano (NL) pig is a black coat colored breed characterized by a remarkable ability to adapt to the difficult territory and climatic conditions of Basilicata region in Southern Italy. In the second half of the twentieth century, technological innovation, agricultural evolution, new breeding methods and the demand for increasingly lean meat brought the breed almost to extinction. Only in 2001, thanks to local institutions such as: the Basilicata Region, the University of Basilicata, the Regional Breeders Association and the Medio Basento mountain community, the NL pig returned to populate the area with the consequent possibility to appreciate again its specific cured meat products. We analyzed the pedigrees recorded by the breeders and the Illumina Porcine SNP60 BeadChip genotypes in order to obtain the genetic structure of the NL pig. Results evidenced that this population is characterized by long mean generation intervals (up to 3.5 yr), low effective population size (down to 7.2) and high mean inbreeding coefficients (FMOL = 0.53, FROH = 0.39). This picture highlights the low level of genetic variability and the critical issues to be faced for the complete recovery of this population.