Body Weight Traits Research Articles

First Genomic Prediction of Single-Step Models in Large Yellow Croaker.

Genome selection is mainly used in disease-resistant traits of aquatic species; however, its implementation is hindered by a high cost of genotype and phenotype data collection. Single-step genomic best linear unbiased prediction (SSGBLUP) can integrate phenotypes, genetic markers, and pedigree records into simultaneous prediction without increasing genotyping costs. The objective of this study is to investigate the performance of SSGBLUP in large yellow croaker and to evaluate the effects of the number of phenotypic records and genotyping per family on the predictive ability of SSGBLUP. A large yellow croaker population consists of 6898 individuals from 14 families with survival time resistant against Cryptocaryon irritans (C. irritans), body weight (BW), and body length (BL) traits were collected, of which 669 individuals were genotyped. Results showed that the mean predictive ability of all traits in the individuals randomly sampling for SSGBLUP, GBLUP, and BLUP was 0.738, 0.738, and 0.736, respectively. Moreover, the predictive ability of SSGBLUP and BLUP models did not increase with the extra phenotypic records per family, in which the predictive ability of SSGBLUP and BLUP in survival time was 0.853 and 0.851 for only genotyped data (N = 0) used, and 0.852, 0.845 for all phenotypic records (N = 600) used, respectively. However, with the increase in the genotype number of training set, the prediction ability of SSGBLUP and GBLUP model was increased and the highest predictive ability was gained when the genotype number per family was 40 or 45. In addition, the prediction ability of SSGBLUP model was higher than that of GBLUP. Our study showed that the SSGBLUP model still has great potential and advantages in genomic breeding of large yellow croakers. It is recommended that each family provide 100 phenotypic individuals, of which 40 individuals with genotyping data for SSGBLUP model prediction and family resistance evaluation.

Impact of inclusion non-additive effects on genome-wide association and variance’s components in Scottish black sheep

Context It’s well-documented that most economic traits have a complex genetic structure that is controlled by additive and non-additive gene actions. Hence, knowledge of the underlying genetic architecture of such complex traits could aid in understanding how these traits respond to the selection in breeding and mating programs. Computing and having estimates of the non-additive effect for economic traits in sheep using genome-wide information can be important because; non-additive genes play an important role in the prediction accuracy of genomic breeding values and the genetic response to the selection. Aim This study aimed to assess the impact of non-additive effects (dominance and epistasis) on the estimation of genetic parameters for body weight traits in sheep. Methods This study used phenotypic and genotypic belonging to 752 Scottish Blackface lambs. Three live weight traits considered in this study were included in body weight at 16, 20, and 24 weeks). Three genetic models including additive (AM), additive + dominance (ADM), and additive + dominance + epistasis (ADEM), were used. Key results The narrow sense heritability for weight at 16 weeks of age (BW16) were 0.39, 0.35, and 0.23, for 20 weeks of age (BW20) were 0.55, 0.54, and 0.42, and finally for 24 weeks of age (BW24) were 0.16, 0.12, and 0.02, using the AM, ADM, and ADEM models, respectively. The additive genetic model significantly outperformed the non-additive genetic model (p < 0.01). The dominance variance of the BW16, BW20, and BW24 accounted for 38, 6, and 30% of the total phenotypic, respectively. Moreover, the epistatic variance accounted for 39, 0.39, and 47% of the total phenotypic variances of these traits, respectively. In addition, our results indicated that the most important SNPs for live weight traits are on chromosomes 3 (three SNPS including s12606.1, OAR3_221188082.1, and OAR3_4106875.1), 8 (OAR8_16468019.1, OAR8_18067475.1, and OAR8_18043643.1), and 19 (OAR19_18010247.1), according to the genome-wide association analysis using additive and non-additive genetic model. Conclusions The results emphasized that the non-additive genetic effects play an important role in controlling body weight variation at the age of 16–24 weeks in Scottish Blackface lambs. Implications It is expected that using a high-density SNP panel and the joint modeling of both additive and non-additive effects can lead to better estimation and prediction of genetic parameters.

Genomic evaluation of body weight traits in a F2 mixture of commercial broiler and native chicken

Abstract Genetic improvement of body weight (BW) traits has received major consideration in the poultry industry due to their economic and environmental implications. With the rapid implementation of genomic selection (GS) in the poultry industry and a decrease in the cost of genotyping, genomic prediction (GP) is a feasible way to increase productivity. Moreover, a pre-selection of SNPs could represent a reasonable option to speed up GP. We used 312 F2 broiler chicken genotyped with 60K Illumina Beadchip to investigate the effect of reduced SNP densities on accuracy and bias of prediction using single-step genomic BLUP (ssGBLUP) for BW at 2-4 weeks of age (488 chickens). To investigate the effect of reduced SNP densities by varying minor allele frequency (MAF), SNPs were grouped into five subgroups with MAF of 0.05-0.1, 0.1-0.2, 0.2-0.3, 0.3-0.4 and 0.4-0.5. The accuracy and bias of genomic predictions from different MAF bins were compared to that using a standard array of 60k SNP genotypes and the traditional BLUP method. Our study showed that using a subset of common SNPs genotypes may increase accuracy of genomic predictions compared to using all SNPs, specifically in the studied F2 population with a limited number of genotyped/phenotyped individuals.

Genetic Parameter Estimates of Growth Curve and Feed Efficiency Traits in Japanese Quail.

This study aimed to estimate heritabilities for weekly body weight traits, the Gompertz growth curve parameters, and feed efficiency characteristics, as well as genetic correlations among characteristics. A total of 700 Japanese quails with pedigree records were used in this study. Body weight and feed consumption were measured individually on a weekly basis. Using weekly body weight data, the growth model parameters were estimated for each bird using the Gompertz nonlinear regression model. Multi-trait variance-covariance matrices were obtained with Bayesian inference using the Gibbs sampler. While estimates of high heritability (0.59 to 0.61) were found for weekly body weight traits, estimates of moderate heritability (0.23 to 0.37) were determined for feed intake and feed conversion efficiency traits. The estimated heritabilities for the parameters of the Gompertz model and inflection point coordinates were moderate (0.37 to 0.47). While genetic correlations between feed intake and body weight characteristics were positive and moderate (0.28 to 0.49), the genetic correlations between feed conversion efficiency and body weight traits were positive and strong (0.52 to 0.83). It has been concluded that the moderate negative genetic relationship between feed conversion efficiency and body weight may constrain selection studies. Due to the weak genetic correlation between the asymptotic body weight parameter of the Gompertz model and the feed conversion efficiency, it is thought that the total genetic gain will be greater if the mature weight parameter is also used as a selection criterion in genetic improvement studies.

Chromosome-scale assembly and quantitative trait locus mapping for major economic traits of the Culter alburnus genome using Illumina and PacBio sequencing with Hi-C mapping information.

Topmouth culter (Culter alburnus) is an economically important freshwater fish with high nutritional value. However, its potential genetic advantages have not been fully exploited. Therefore, we aimed to determine the genome sequence of C. alburnus and examine quantitative trait loci (QTLs) related to major economic traits. The results showed that 24 pseudochromosomes were anchored by 914.74Mb of the C. alburnus genome sequence. De novo sequencing identified 31,279 protein-coding genes with an average length of 8507 bp and average coding sequ ence of 1115bp. In addition, a high-density genetic linkage map consisting of 24 linkage groups was constructed based on 353,532 high-quality single nucleotide polymorphisms and 4,710 bin markers. A total of 28 QTLs corresponding to 11 genes, 26 QTLs corresponding to 11 genes, and 12 QTLs corresponding to 5 genes were identified for sex, intermuscular spine number and body weight traits, respectively. In this study, we assembled an accurate and nearly complete genome of C. alburnus by combining Illumina, PacBio, and high-throughput Chromosome conformation capture (Hi-C) technologies. In addition, we identified QTLs that explained variances in intermuscular spine number, body weight, and sex differences in C. alburnus. These genetic markers or candidate genes associated with growth traits provide a basis for marker-assisted selection in C. alburnus.

Single Nucleotide Polymorphisms in Skeletal Muscles of Myogenin and Myostatin Genes of the Nile Tilapia (Oreochromis niloticus)

The present study was conducted on the Nile tilapia (Oreochromis niloticus) and screened for single nucleotide polymorphisms (SNPs) in the muscle hormone genes myogenin (MyoG) and myostatin (MSTN). Samples were collected from the JangHang fish farm and categorized by body weight and sex. The average total weight was 1.02 kg for the 82 males and 0.63 kg for the 70 females. A body weight in the range of the average weight ±10% was considered as normal weight. Target regions of each gene were categorized, such as the promoter region, 5′-untranslated region (5′UTR) and 3′UTR. Genomic deoxyribonucleic acid (gDNA) was extracted, amplified, sequenced, aligned, and screened for the presence of nucleotide variations. Three SNPs, 1,875T&gt;A, 1,892C&gt;T, and 1,946A&gt;G, and one insertion (TGA​CAT​ATT​TCC​CTC​ACA) at 2,138–2,145 were detected in the 3′UTR of the MyoG gene. However, within the MSTN gene, one insertion at 450 (T) and two SNPs at 536 (G&gt;A and A&gt;A) were found in the 5′UTR. In addition, four insertions at 1,278–1,279 (GT, T, TGT, and G) and one short tandem repeat (STR) at 1,129 (TG) in Exon 1, two SNPs at 4,438 (3′UTR; A&gt;C and C&gt;C), and two SNPs at 4,514 (3′UTR; G&gt;A and A&gt;A) were identified. Principal component analysis (PCA) and statistical analyses were performed to evaluate the relationships between the SNPs and body weight, forming 6 and 41 genotype blocks in the MyoG and MSTN genes, respectively. We found significant correlations between the SNPs and body weight traits for the effective genotype blocks GBG-1, GBG-3, and GBG-4 of MyoG and GBN-1, GBN-2, GBN-3, GBN-4, GBN-13, GBN-22, and GBN-24 of MSTN. These outcomes would be significant for fish breeding and may help obtain data for use in genetic marker kits. In some instances, genetic marker kits have a distinct advantage for improvement in genetics, parentage control, identification of species, and enhancing breeding stock and its applications in aquaculture.

Genome-wide association study for growth-related traits in golden pompano (Trachinotus ovatus)

Growth-related traits are complex and economically important traits in the aquaculture industry. Improvement of growth traits is generally considered as the main objective in breeding programs of farmed fish. The molecular basis underlying Golden pompano (Trachinotus ovatus) growth traits remains largely unknown. T. ovatus is a commercial marine fish species with a considerable market value. It is necessary to select new varieties of T. ovatus with fast growth traits, which could contribute to increased production and lower costs. In this study, the whole genome resequencing (WGS) was applied for genotyping 716 T. ovatus individuals and 4,886,850 high-quality single nucleotide polymorphism (SNP) located on 24 chromosomes were developed. A genome-wide association study (GWAS) was performed to detect SNPs and genes that are potentially related with growth traits, including body weight (BW) and body length (BL). Results indicated that 107 SNPs were significantly associated with growth traits, of which 18 SNPs were commonly shared with BW and BL traits. Furthermore, 108 genes were annotated by the identified SNPs. GO enrichment analysis suggested that the terms related with muscle growth, anabolism, and bone development were significantly enriched. Most candidate genes were known to be involved in muscle growth and bone development, some of which were reported to be associated with muscle hypertrophy in humans. This study provides useful information to understand the genetic architecture of growth-related traits and provides effective molecular markers for future genome-wide selection breeding of T. ovatus.

Exploring the growth trait molecular markers in two sheep breeds based on Genome-wide association analysis.

Growth traits are quantitative traits controlled by multiple micro-effect genes. we identified molecular markers related to sheep growth traits, which formed the basis of molecular breeding. In this study, we randomly selected 100 Qira Black sheep and 84 German Merino sheep for the blood collection the jugular vein to genotype by using the Illumina Ovine SNP 50K Bead Chip. quality control criteria for statistical analysis were: rejection detection rate < 90% and minimum allele frequency (MAF) < 5%. Then, we performed Genome-wide association studies (GWAS) on sheep body weight, body height, body length, and chest circumference using mixed linear models. After getting 55 SNPs with significant correlation, they were annotated by reference genome of Ovis aries genome (Oar_v4.0) and We obtained a total of 84 candidate genes associated with production traits (BMPR1B, HSD17B3, TMEM63C, etc.). We selected BMPR1B for population validation and found a correlation between the FecB locus and body weight traits. Therefore, this study not only supplements the existing knowledge of molecular markers of sheep growth traits, but also has important theoretical significance and reference value for the mining of functional genes of sheep growth traits.

Effect of Beak Color on Growth Performance and Carcass Characteristics of Pekin Ducks

Background: Pekin ducks are broadly raised over the world, particularly in Asia continent, moreover, they are famous for the delightful taste of Beijing roast duck around the world. The aim of this study was to explore the effect of beak color on growth performance, carcass traits and sexual dimorphism of Pekin ducks. Methods: A total of 250 one-day-old Pekin ducks were separated according to beak color into two groups, yellow beak (YB) and blue beak (BB). Body weight and body weight gain were recorded from the first week to the marketing age (6 wks). Carcass traits were taken at the marketing age (20 ducks /each phenotype). Sexual dimorphism was calculated for live body weight and carcass traits at marketing age. Result: show that YB ducks have significantly heavier body weight at 1 and 5 wks of age compared to BB, however the body weight of BB ducks was higher at 3 and 4 wks of age. At marketing age, the differences in body weight between two phenotypes were not significant. Generally, BB ducks have significantly higher body weight gain and growth rate compared to YB ducks. The mortality and defect ratio were affecting beak color, the blue beak ducks recorded higher relative mortality rate and lower defect ratio compared to yellow beak ducks. There was no effect of beak color on carcass traits. However, the sexual dimorphism was significantly higher for the YB ducks for most traits compared to BB. In conclusion, we concluded has a significant effect beak color on growth performance and sexual dimorphism of Pekin ducks.

Genetic Parameters of Growth Traits and Quantitative Genetic Metrics for Selection and Conservation of Mecheri Sheep of Tamil Nadu.

Determining the genetic and non-genetic sources of variation in a breed is vital for the formulation of strategies for its conservation and improvement. The present study was aimed at estimating the (co)variance components and genetic parameters of Mecheri sheep by fitting six different animal models in the restricted maximum likelihood method, with a preliminary investigation on the performance of animals for non-genetic sources of variation. A total of 2616 lambs were studied, and varying levels of significance were found for the effects of period, season, parity of dam, and birth type on different body-weight traits. Direct heritability estimates derived from the best animal model for body weight at birth, three months, six months, nine months, and twelve months were 0.21, 0.24, 0.10, 0.15, and 0.09, respectively, and the maternal heritability of the corresponding traits was 0.12, 0.05, 0.04, 0.04, and 0.04, respectively. The genetic correlations between the body-weight traits were all positive and moderate-to-strong, except for the correlation between birth weight and the other body-weight traits. The significance of non-genetic factors studied in this work demanded a correction to improve the accuracy of the direct selection of lambs for body-weight traits. The estimated genetic parameters identified the weaning weight as a selection criterion for the improvement in body weight of Mecheri lambs at different ages. Inbred individuals accounted for approximately 13% of the total population in the Mecheri sheep population studied. There were 877 founders in the population, and the actual effective population size was 128.48. The population's mean generation interval was 3.26. The mean inbreeding values ranged from 0.005 to 0.010 across generations. The population's average relatedness ranged from 0.001 to 0.014 across generations. Individual inbreeding was found to be 0.45 per cent for the entire population and 3.4 per cent for the inbred population.

Uganda chicken genetic resources: I. phenotypic and production characteristics.

The extent of diversity in the indigenous chicken breeds of Uganda was assessed for their potential utilisation in breeding programmes. A total of 293 indigenous-chicken-keeping households in villages across 35 districts forming 12 sub-regions of the four regions were randomly sampled for 586 mature chickens of both sexes. While only 20.8% of households were headed by women, 40.6% of indigenous chicken keepers were women. The production objectives mainly focused on chickens as sources of income from sales and household food. The chickens were predominantly managed in a scavenging (94.2%) feeding system in a mainly (96.9%) mixed crop-livestock system. The average flock size was 19.80 ± 1.21 chickens with 3.83 ± 0.29 laying hens, each producing an average of 13.41 ± 0.20 eggs/clutch and 40.3 ± 0.6 eggs/annum of 5.20 ± 0.03-month egg production age. Normal-feather strains predominated (>90%), with scattered incidences of naked neck, frizzles, polydactyl, and ptilopody traits in both sexes. Dark (49.0% hen; 43.8% cock) and white (38.3% hen; 42.4% cock) skin colours were most common among the chickens compared to yellow skin. However, yellow-coloured shanks were proportionally the most observed (41% cock; 29% hen). Orange and brown iris (eye) colours were the most common in both sexes. The hens commonly had small round earlobes with varying colours, while cocks had large oval-shaped, mainly red (70%) earlobes. The single-comb type was dominant in both sexes, with wattles almost universally present. Frizzle and polydactyl allele frequencies were significantly lower (p < 0.05) than the expected Mendelian proportions, indicating a possible state of endangerment. Meanwhile, the estimated allele frequencies of ptilopody, tufted-crest, and rose comb alleles in the population were similar (p > 0.05) to the expected Mendelian frequencies. However, these strains did not show any significant (p > 0.05) influence on the body weight or the linear morphometric estimates except for being marginally higher than the normal strains. The phenotypic correlations of body weight and morphometric traits ranged from 0.457 to 0.668 and 0.292 to 0.454 in cocks and hens, respectively. These findings provide hints about the prospects for improved performance with modifications in the production environment. The wide phenotypic diversity would support management efforts for their sustainable utilisation and preservation.

Genetic progress evaluation of growth traits in Moghani sheep

For evaluation of growth traits' genetic progress, pedigree information of 39408 Moghani sheep, between 1986 to 2016, at the breeding station of Moghani sheep was used. Studied traits included birth weight, weaning weight, six months weight, nine months weight, and one yearling weight. Variance components and genetic parameters of traits were estimated by restricted likelihood and six animal models using Wombat software. Direct heritability of birth weight, weaning weight, six months weight, nine months weight, and one yearling weight was (0.07, 0.09, 0.15, 0.13, and 0.20 respectively). Breeding values for the calculation of genetic trends for each trait were estimated by using the univariate best animal model. Phenotypic, genetic, and environmental trends of traits were estimated via regression of phenotypic average, breeding value average, and difference of breeding value from phenotypic value divided by birth year. The calculated genetic trends of birth weight, weaning weight, six months weight, nine months weight, and yearling weight were 0.008, 0.012, 0.054, 0.74, and 0.145 kg/year respectively, except for birth weight, the others were significant (p&lt;0.01). The genetic gain of traits including birth weight, weaning weight, six months weight, nine months weight, and one yearling weight was estimated (0.213, 1.071, 1.171, 1.164, and 1.324 kg respectively). At evaluated years, many fluctuations were observed in the genetic trend of traits. In other words, it seems at the studied years, there wasn't a comprehensive plan for genetic breeding and improvement of body weight traits in Moghani sheep.

Comparison of the Production Performance of the third Generation Among four lines Selection on the Basis of Plumage Color in Quail

This study aimed to evaluate the productive performance of the third-generation of quails selected according to the color of the plumage to produce a hybrid line distinguished by the productive performance depending on the color of the plumage. 48 females of different plumage (Black, Golden, White and Brown) were compared and transferred at the age of five weeks. To a hall dedicated to breeding containing rooms with dimensions of 40 x 40 x 40 cm and numbered. The females were randomly distributed to the rooms individually and for each line (12 females). The results of the study showed that there were significant (p≤0.05) differences in the effect of the colour of the plumage selection according to each line (golden, brown, white and black) in the average body weight at the age of five and six weeks, body weight at sexual maturity, weight of eggs produced within 60 days, and the number of days required to produce the first 60 eggs And mass of eggs during 60 days, while there was no significant effect between the plumage colour lines in the trait of average age at sexual maturity, weight of the first egg, number of days needed to produce the first 30 eggs, and number of eggs produced during 60 days. As for the phenotypic correlations, a positive and highly significant phenotypic correlation was found between the traits of body weight at five and six weeks of age and body weight at sexual maturity, as well as between egg weight, body weight at sexual maturity and egg mass.

Bayesian estimates for genetic and phenotypic parameters of growth traits in Sahiwal cattle.

Analyses were carried out for the estimation of (co)variance components and genetic parameters for birth weight (BWT), 6-month weight (6WT), 12-month weight (12WT), 18-month weight (18WT), 24-month weight (24WT), 30-month weight (30WT), 36-month weight (36WT), weight at first service (WFS), and weight at first calving(WFC) in Sahiwal cattle. Data for 802 lifetime records (raw data) were collected over a period of 30years (1990-2019) for various growth traits in the herd for Sahiwal cows maintained at the livestock farm unit of ICAR-NDRI Karnal, Haryana, India. Bayesian estimates using the multi-trait Gibbs sampling animal model approach were calculated in the present study. Total heritability for BWT, 6WT, 12WT, 18WT, 24WT, 30WT, 36WT, WFS, and WFC by Bayesian modeling was estimated as 0.22 ± 0.0052, 0.47 ± 0.0037, 0.30 ± 0.0025, 0.65 ± 0.0021, 0.32 ± 0.0039, 0.33 ± 0.0027, 0.39 ± 0.0031, 0.49 ± 0.0020, and 0.57 ± 0.0023, respectively, along with its Monte Carlo error in Sahiwal cattle. Direct genetic covariances between body weight traits were ranging from - 2762.5 for 18WT and WFC to 4739.6 between WFS and WFC. Environmental covariances were ranging from - 169.98 for 30WT and 36WT to 4539.4 between WFS and WFC. Family relationships as well as the existing interaction effects between two or more traits in opposite direction effect lead to negative estimates for genetic covariances between some of the combinations with various growth traits. Although most of the estimates for posteriori were somewhat skewed, the marginalization effect enabled them to fit into the Gaussian distribution, by comparing the mean, mode, and median with each other. Results suggest that genetic progress through growth traits can be achieved if the selection is carried out for highly heritable 18-month weight as well as for the selection of pubertal and fertility traits, viz., 24WT, 30WT, 36WT, WFS, and WFC with a balanced feeding and optimum management.

The estimation of genetic parameters and genetic trends for growth traits in Markhoz goats

One of the most important breeds of Iranian goats is the Markhoz goat. Estimation of genetic parameters and genetic trend helps to select the best Breeding plan. The present study aimed to estimate the (co)variance components, genetic and environmental parameters, and the genetic trend of Markhoz goat body weight traits at different ages. To this aim the Bayesian statistical method was used. This research used the information about the birth weight (BW), weaning weight (WW), 6-month weight (6 MW), 9-month weight (9 MW), and yearling weight (YW) of 5.549 offspring of 262 bucks and 1620 does. The data were collected in 1992–2020 from the Markhoz breeding center, in Kurdistan Province. A total number of 5.159, 3.948, 3.759, 3.337 and 5.159 records of BW, WW, 6 MW, 9 MW, and YW were used, respectively. SAS9.4 statistical package was used to explore significant environmental factors affecting these traits. MTGSAM software and Gibbs sampling was used to estimate genetic parameters. Environmental factors including birth year, sex, birth type and the doe age at parturition were significant to all the mentioned traits and were included as fixed effect in the model. Direct heritability’s were estimated to be 0.29, 0.15, 0.16, 0.34, 0.33, for BW, WW, 6 MW, 9 MW, and YW, respectively. The genetic trend of these traits was 1, 27, 39, 81 and 78 g per year, respectively. The genetic and phenotypic correlations of the studied traits ranged from medium to high. Gibbs sampling could estimate the parameters in a reasonable range. The research findings suggested that growth traits in Markhoz goats, at different ages, were affected by the maternal genetic effects. The medium to high heritability obtained for the studied traits shows that selecting these traits can lead to a low to medium genetic improvement.

Identification of SNPs and candidate genes associated with early growth in orange-spotted grouper (Epinephelus coioides) by a genome-wide association study

Orange-spotted grouper, Epinephelus coioides is one of the most economically important marine fish in the South China Sea. Exploring of the genetic basis controlling for the growth-related traits is helpful for the genetic breeding of the grouper. To date, the quantitative trait loci (QTLs) and single nucleotide polymorphisms (SNPs) that associated with early growth in the orange-spotted grouper are unclear. In this study, dissection of the genetic architecture of the early growth-related traits (body weight, body length and body height) were carried out for 288 orange-spotted groupers at 3 months post hatching by using an selective phenotyping-based genome-wide association study (GWAS). 5279 high-quality SNPs were identified for the population. A total of 11 SNPs that located on three chromosomes (Chr1, Chr9 and Chr22) were significantly associated with early growth-related traits. The proportion of phenotypic variance explained for these SNPs ranged from 5.15% to 6.89% for body weight, 5.23% to 6.95% for body length, and 5.29% to 6.21% for body height. Five of these SNPs were associated with all traits, and 3 SNPs were associated with body weight trait and body height trait. Based on these associated SNPs, some important candidate genes (e.g., mustn1, bmp7, sema3a, magi2, prkcd, capzb, twf2 and eps8l2) were predicted. To assess the reliability of candidate SNP datasets identified by GWAS analysis, we further verified the SNPs by using Sanger sequencing technology. This study provides important insights into the genetic basis of early growth-related traits in the orange-spotted grouper.

Genetic Evaluation of Body Weight Traits in Local Rabbit

This study was carried out on seventy-six local rabbit (white, black and white and brown white coat color) to investigate the effect of some non-genetic factors on body weight traits in local rabbits with the genetic evaluation of local rabbits by estimated BLUP value of marketing weight. The overall mean of marketing weight, dressing % and average daily gain arrived 1476.01 ± 33.10 g/rabbit, 51.32 ± 0.84 % and 17.22 ± 0.69 g/day/rabbit, respectively. The black-white coat color rabbits excelled in most of the studied traits, especially in weight at marketing (1615.88 ± 31.96 g/rabbit), daily weight gain (19.90 ± 0.64 g/rabbit) and carcass weight (820.588 ± 15.813 g/rabbit) over the other colors, while the highest dressing ratio was in the white rabbits (52.83 ± 0.67 % /rabbit). A significant and numerical superiority of male rabbits over female in the traits under study. A significant positive correlation was recorded among most traits under study. The BLUP values for rabbit ranged from -700 to 100 g/rabbit. These result indicated that there are big genetic variations in this population of local rabbit. It indicates that selection can play a major role in improving body weight traits in local rabbit.

SNP- and haplotype-based single-step genomic predictions for body weight, wool, and reproductive traits in North American Rambouillet sheep.

Rambouillet sheep are commonly raised in extensive grazing systems in the US, mainly for wool and meat production. Genomic evaluations in US sheep breeds, including Rambouillet, are still incipient. Therefore, we aimed to evaluate the feasibility of performing genomic prediction of breeding values for various traits in Rambouillet sheep based on single nucleotide polymorphisms (SNP) or haplotypes (fitted as pseudo-SNP) under a single-step GBLUP approach. A total of 28,834 records for birth weight (BWT), 23,306 for postweaning weight (PWT), 5,832 for yearling weight (YWT), 9,880 for yearling fibre diameter (YFD), 11,872 for yearling greasy fleece weight (YGFW), and 15,984 for number of lambs born (NLB) were used in this study. Seven hundred forty-one individuals were genotyped using a moderate (50 K; n=677) or high (600 K; n=64) density SNP panel, in which 32 K SNP in common between the two SNP panels (after genotypic quality control) were used for further analyses. Single-step genomic predictions using SNP (H-BLUP) or haplotypes (HAP-BLUP) from blocks with different linkage disequilibrium (LD) thresholds (0.15, 0.35, 0.50, 0.65, and 0.80) were evaluated. We also considered different blending parameters when constructing the genomic relationship matrix used to predict the genomic-enhanced estimated breeding values (GEBV), with alpha equal to 0.95 or 0.50. The GEBV were compared to the estimated breeding values (EBV) obtained from traditional pedigree-based evaluations (A-BLUP). The mean theoretical accuracy ranged from 0.499 (A-BLUP for PWT) to 0.795 (HAP-BLUP using haplotypes from blocks with LD threshold of 0.35 and alpha equal to 0.95 for YFD). The prediction accuracies ranged from 0.143 (A-BLUP for PWT) to 0.330 (A-BLUP for YGFW) while the prediction bias ranged from -0.104 (H-BLUP for PWT) to 0.087 (HAP-BLUP using haplotypes from blocks with LD threshold of 0.15 and alpha equal to 0.95 for YGFW). The GEBV dispersion ranged from 0.428 (A-BLUP for PWT) to 1.035 (A-BLUP for YGFW). Similar results were observed for H-BLUP or HAP-BLUP, independently of the LD threshold to create the haplotypes, alpha value, or trait analysed. Using genomic information (fitting individual SNP or haplotypes) provided similar or higher prediction and theoretical accuracies and reduced the dispersion of the GEBV for body weight, wool, and reproductive traits in Rambouillet sheep. However, there were no clear improvements in the prediction bias when compared to pedigree-based predictions. The next step will be to enlarge the training populations for this breed to increase the benefits of genomic predictions.

Genetic and Phenotypic Parameters for Pelt Quality and Body Length and Weight Traits in American Mink.

Understanding the genetics of fur characteristics and skin size is important for developing effective breeding programs in the mink industry. Therefore, the objectives of this study were to estimate the genetic and phenotypic parameters for pelt quality traits including live grading overall quality (LQU), live grading nap size (LNAP), dried pelt size (DPS), dried pelt nap size (DNAP) and overall quality of dried pelt (DQU), and body length and weight traits, including November body weight (Nov_BW), November body length (Nov_BL), harvest weight (HW) and harvest length (HL) in American mink. Dried pelt quality traits on 1195 mink and pelt quality traits on live animals on 1680 were collected from mink raised at two farms, in Nova Scotia and Ontario. A series of univariate analyses were implemented in ASReml 4.1 software to identify the significance (p < 0.05) of random effects (maternal genetic effects, and common litter effects) and fixed effects (farm, sex, color type, year, and age) for each trait. Subsequently, bivariate models were used to estimate the genetic and phenotypic parameters using ASReml 4.1. Heritability (±SE) estimates were 0.41 ± 0.06 for DPS, 0.23 ± 0.10 for DNAP, 0.12 ± 0.04 for DQU, 0.28 ± 0.06 for LQU, 0.44 ± 0.07 for LNAP, 0.29 ± 0.10 for Nov_BW, 0.28 ± 0.09 for Nov_BL, 0.41 ± 0.07 for HW and 0.31 ± 0.06 for HL. DPS had high positive genetic correlations (±SE) with Nov_BW (0.89 ± 0.10), Nov_BL (0.81 ± 0.07), HW (0.85 ± 0.05) and HL (0.85 ± 0.06). These results suggested that body weight and length measured on live animals in November of the first year were reliable indicators of dried pelt size. DQU had favorable genetic correlations with Nov_BL (0.55 ± 0.24) and HL (0.46 ± 0.20), and nonsignificant genetic correlations with DNAP (0.13 ± 0.25), Nov_BW (0.25 ± 0.25) and HW (0.06 ± 0.20), which made body length traits an appealing trait for selection for increased pelt size. High positive genetic correlation (±SE) was observed between LNAP and DNAP (0.82 ± 0.22), which revealed that nap size measurement on live animals is a reliable indicator trait for dried pelt nap size. However, nonsignificant (p > 0.05) low genetic correlation (±SE) was obtained between LQU and DQU (0.08 ± 0.45), showing that indirect selection based on live grading might not lead to the satisfactory improvement of dried pelt overall quality. The estimated genetic parameters for live grading, dried pelt quality, and body weight and body length traits may be incorporated into breeding programs to improve fur characteristics in Canadian mink populations.

Single Nucleotide Polymorphisms in Insulin-like Growth Factor 2 (IGF2) gene and their associations with body weight and growth rate traits in indigenous guinea fowls (Numida meleagris) of northern Ghana

Insulin-like Growth Factor 2 (IGF2) plays important roles in stimulating cell proliferation, differentiation and migration culminating its effects as a modulator of juvenile growth in animals. Although the gene that codes for IGF2 (IGF2) has been investigated as a candidate gene in several livestock species, there is no information on polymorphisms in IGF2 in guinea fowls (gIGF2), an important indigenous poultry species from West Africa. Therefore, this study sought to identify the Single Nucleotide Polymorphisms (SNPs) in three populations of indigenous guinea fowls in northern Ghana. Target genomic regions in gIGF2 were amplified and sequenced from 84 indigenous guinea fowls from Upper East Region (n = 17), former Northern Region (n = 22) and Upper West Region (n = 45) of Ghana together with domesticated French variety (n = 3). The sequences were aligned with the reference genomic sequence (domesticated French variety) of chromosome 6 (GenBank accession no., NC_034414.1) to identify SNPs. Statistical associations among the genotypes arising from the SNPs and juvenile growth traits were estimated using linear models. Two novel SNPs were identified in gIGF2 among the indigenous guinea fowls. An insertion of a Guanine (G) within a poly G motif of the intron following the third exon at the 13,955,730 bp location was identified in the majority (84.5%) of indigenous guinea fowls, while the wild type allele was observed in the minority of indigenous guinea fowls and in the domesticated French variety sampled. Also, a biallelic transition arising from the substitution of G by Adenine (A) at position 13,956,496 bp (13,956,496 G > A) located on the fourth exon, which codes for most of the extension peptide of prepro IGF2, was observed in the minority (11.9%) of indigenous guinea fowls. No significant associations among the genotypes arising from the two SNPs, with body weights and weekly growth rates, were identified.