Traits Of Economic Importance Research Articles

Effects of the CDC10 (Septin 7) Gene on the Proliferation and Differentiation of Bovine Intramuscular Preadipocyte and 3T3-L1 Cells.

Intramuscular fat content and marbling affecting meat quality are important economic traits in beef cattle. CDC10 (cell division cycle 10 or Septin 7), a member of the septin family involved in cellular proliferation, was considered as a functional and positional candidate gene for beef marbling. In a previous study, we revealed that the expression levels of CDC10 were also positively correlated with marbling scores in Japanese Black cattle. However, the regulatory mechanism of the CDC10 gene on IMF deposition in cattle remains unclear. In the present study, flow cytometry, EdU proliferation assays, and Oil Red O staining results showed that overexpression of CDC10 could promote the differentiation of bovine intramuscular preadipocyte (BIMP) and 3T3-L1 cells, whereas knockdown of CDC10 resulted in the opposite consequences. Furthermore, quantitative PCR and Western blotting results showed that overexpression of CDC10 could promote the expression levels of adipogenic marker genes PPARγ and C/EBPα at both mRNA and protein levels in BIMP and 3T3-L1 cells, whereas knockdown of CDC10 resulted in the opposite consequences. Our results provide new insights into the regulatory roles of CDC10 in adipocytes in animals.

The cecal ecosystem is a great contributor to intramuscular fat deposition in broilers

Intramuscular fat (IMF) content is a meat quality trait of major economic importance in animal production. Emerging evidence has demonstrated that meat quality can be improved by regulating the gut microbiota. However, the organization and ecological properties of the gut microbiota and its relationship with the IMF content remain unclear in chickens. Here, we investigated the microbial communities of 206 cecal samples from broilers with excellent meat quality. We noted that the cecal microbial ecosystem obtained from hosts reared under the same management and dietary conditions showed clear compositional stratification. Two enterotypes, in which the ecological properties, including diversity and interaction strengths, were significantly different, described the microbial composition pattern. Compared with enterotype 2, enterotype 1, distinguished by the Clostridia_vadinBB60_group, had a higher fat deposition, although no discrepancy was found in growth performance and meat yield. A moderate correlation was observed in the IMF content between 2 muscle tissues, despite the IMF content of thigh muscle was 42.76% greater than that of breast muscle. Additionally, the lower abundance of cecal vadinBE97 was related to higher IMF levels in both muscle tissues. Although vadinBE97 accounted for 0.40% of the total abundance of genera in the cecum, it exhibited significant and positive correlations with other genera (accounting for 25.3% of the tested genera). Our results highlight important insights into the cecal microbial ecosystem and its association with meat quality. Microbial interactions should be carefully considered when developing approaches to improve the IMF content by regulating the gut microbiota in broilers.

Association analysis of polymorphisms of candidate genes for laying traits in Yangzhou geese

Egg production is an important economic trait in the Chinese goose industry. Due to the low heritability of annual egg production traits in geese, large-scale individual selection based on annual egg production measurements cannot be carried out. Therefore, new selection methods must be applied for large-scale early selections. To screen for effective molecular markers for early Yangzhou geese selection, the genotypes and gene frequencies of mutated loci of five candidate genes related to egg production, MAGI-1, ACSF2, ASTN2, KIAA1462, and ARHGAP21, were detected and analyzed by PCR-direct sequencing.Furthermore, correlation analysis was performed with annual egg mass and body weight at the point of lay and egg weight, and the results were as follows:Magi-1 (Record-106975)was A > G, ACSF2 (Record-106582)was A > C, ASTN2 (Record-111407)was A > T, KIAA1462 (Record-134172)was A > T, and the base of ARHGAP21 (Record-112359) was G > T. At all the five loci above, the Yangzhou geese population followed the Hardy-Weinberg equilibrium (P > 0.05). The results of the association analysis between different genotypes and production performance showed no significant differences in annual egg production, body weight at the point of lay, and egg weight, among different genotypes (P > 0.05) at the mutation loci of MAGI-1 and ASTN2. At the ACSF2 and KIAA1462, the annual egg production of AC was significantly higher than that of AA and CC (P < 0.05), the annual egg production of TT was significantly higher than that of AA (P < 0.05), and there were no significant differences in body weight at the point of lay and egg weight, among the three genotypes (P > 0.05). At ARHGAP21, the body weight at the lay point of the TT genotype was the highest, which was significantly higher than that of GG (P < 0.05); however, there was no significant difference with the heterozygous GT genotype for this trait (P > 0.05). Therefore, Genotype AC at ACSF2 and genotype TT at KIAA1462 could be used as favorable genotypes for egg production, and genotype TT at ARHGAP21 could be used as a favorable genotype for weight in Yangzhou geese.

STUDIES ON THE PERFORMANCE OF MULTIVOLTINE BREEDS OF SILKWORM, BOMBYX MORI L.

With the objective of identifying potential parental breeds for breeding, a total of 81 multivoltine silkworm germplasm stocks conserved at Central Sericultural Germplasm Resources Centre, Hosur were evaluated in three replications by rearing in five crops during different seasons of the year. Data on the performance was collected and assessed for 12 quantitative traits of economic importance by employing multiple trait evaluation index method. Significant variations among the multivoltine breeds were observed and based on higher Evaluation Index values for economic parameters, the better performing breeds viz., BMI-023, BMI-080 and BMI-081 with higher values in more traits have been identified as promising breeds. The results of the study lay emphasis on utilization of these breeds expressing higher E. I. values in more number of quantitative traits for further breeding and large scale trials. &#x0D;

The genetic basis and potential molecular mechanism of yellow-albino northern snakehead (Channa argus).

Body colour is an important economic trait for commercial fishes. Recently, a new colour morph displaying market-favoured yellow skin (termed as yellow-mutant, YM) of northern snakehead (Channa argus) was discovered in China. We confirmed that YM snakehead is an albino with complete loss of melanin in the skin and eyes by histological and ultrastructural observations, and inherited as a recessive Mendelian trait. By applying genomic analysis approaches, in combination with gene knockdown and rescue experiments, we suggested a non-sense mutation in slc45a2 (c.383G > A) is the causation for the YM snakehead. Notably, significantly higher levels of key melanogenesis genes (tyr, tyrp1, dct and pmel) and phospho-MITF protein were detected in YM snakehead than those in wild-type individuals, and the underlying mechanism was further investigated by comparative transcriptomic analysis. Results revealed that differential expressed genes involved in pathways like MAPK, WNT and calcium signalling were significantly induced in YM snakehead, which might account for the increased amount of melanogenesis elements, and presumably be stimulated by fibroblast-derived melanogenic factors in a paracrine manner. Our study clarified the genetic basis of colour variation in C. argus and provided the preliminary clue indicating the potential involvement of fibroblasts in pigmentation in fish.

Identification of quantitative trait loci for growth traits in red swamp crayfish (Procambarus clarkii)

Genetic breeding is an important approach to improve the economic traits of aquaculture animals. Unfortunately, the genetic basis for important economic traits of red swamp crayfish, including growth-related traits, has not yet been reported. In the present study, two full-sib families and two natural populations were employed to identify quantitative trait loci (QTLs) for growth-related traits of red swamp crayfish. In total, 28 QTLs for five growth-related traits, including body weight, body length, carapace length, carapace width, and abdomen length, were repeatedly identified in more than two families/populations, by means of association analysis; nine of these displayed a heterosis effect. The phenotypic variations of the five investigated traits explained by the 28 QTLs ranged from 4.2% to 19.0%. Eight additive and three heterosis QTLs were further successfully validated using comparative analysis of favoured alleles between the small and big size crayfish groups in the natural population. In conclusion, this study investigated the genetic basis of growth-related traits in red swamp crayfish, which is of great significance for their application in the future molecular breeding of the species.

Genetic study of important economic traits in Hariana cattle

The present investigation was undertaken to access first lactation total milk yield, first lactation length, productive life, herd life and total life. Breeding information were used from the history sheet registers and herd inventory registers of Hariana cattle maintained at DUVASU farm, Mathura and Babugarh farm, Hapur. The data of productive animals with date of calving from 1966 to 2018 and date of birth from 1962 to 2013 were collected for the study. The overall averages for FLTMY, FLL, PL, HL and TL were estimated as 971.2±16.9 litres, 328.2±3.8 days, 2019.1±42.1 days, 2251.8±43.9 days and 3915.7±44.2 days, respectively. The overall least-squares mean of 961.3±24.1 litres, 331.6±5.9 days, 2285.2±64.9 days, 2489.9±69.1 days and 4219.4±70.0 days was observed respectively for the above traits. Season of calving had significant effect on first lactation length and period of calving had significant effect on first lactation total milk. Farm, period of birth and AFC age group had significant effect on PL, HL and TL of Hariana cattle. The heritability for FLTMY and FLL was moderate to high in Hariana cattle.

Identification of candidate genes associated with skin yellowness in yellow chickens

The yellow color of the skin is an important economic trait for yellow chickens. Low and non-uniform skin yellowness would reduce economic efficiency. However, the regulatory mechanism of chicken skin yellowness has not been fully elucidated. In this study, we evaluated the skin yellowness of 819 chickens by colorimeter and digital camera, which are from the same batch and the same age of 2 pure lines with significant differences in skin yellowness. A total of 982 candidate differential expressed genes (DEGs) were detected in duodenal tissue by RNA-seq analysis for high and low yellowness chickens. Among the DEGs, we chose fatty acid translocase (CD36) gene and identified a single nucleotide polymorphism (SNP) upstream of the CD36 gene that was significantly associated with skin yellowness at multiple parts of the chicken, and its different genotypes had significant effects on the promoter activity of the CD36 gene. These findings will help to further elucidate the molecular mechanism of chicken skin yellowness and is helpful for improving chicken skin yellowness.

Incorporating genome-wide and transcriptome-wide association studies to identify genetic elements of longissimus dorsi muscle in Huaxi cattle.

Locating the genetic variation of important livestock and poultry economic traits is essential for genetic improvement in breeding programs. Identifying the candidate genes for the productive ability of Huaxi cattle was one crucial element for practical breeding. Based on the genotype and phenotype data of 1,478 individuals and the RNA-seq data of 120 individuals contained in 1,478 individuals, we implemented genome-wide association studies (GWAS), transcriptome-wide association studies (TWAS), and Fisher's combined test (FCT) to identify the candidate genes for the carcass trait, the weight of longissimus dorsi muscle (LDM). The results indicated that GWAS, TWAS, and FCT identified seven candidate genes for LDM altogether: PENK was located by GWAS and FCT, PPAT was located by TWAS and FCT, and XKR4, MTMR3, FGFRL1, DHRS4, and LAP3 were only located by one of the methods. After functional analysis of these candidate genes and referring to the reported studies, we found that they were mainly functional in the progress of the development of the body and the growth of muscle cells. Combining advanced breeding techniques such as gene editing with our study will significantly accelerate the genetic improvement for the future breeding of Huaxi cattle.

Selection Signature Analysis for Important Economic Traits in Sheep (Ovis aries)

Background: Many genomic imprinting left during long-term selective evolution may drive the formation of important economical traits of introduced and indigenous sheep breeds. Methods: In this study, OvineSNP50 BeadChip data of the introduced breeds GMM and DOR and the indigenous breed Sunit were downloaded from public databases. Selective sweep base on Pi and Fst strategy initially screened for a number of candidate genes that could explain the genetic mechanism elucidated the genetic-molecular mechanisms underlying the differentiation of growth development and reproductive traits between introduced and indigenous breeds. Result: In the DOR_VS_GMM group, 32 genes were identified. In the DOR_VS_SUN group, 26 genes were identified. In the GMM_VS_SUN group, 25 genes were identified. GO, KEGG enrichment analysis showed that these genes are mainly involved in the pathways of muscle development and reproductive regulation. We speculate that EHBP1, CSRP1, TNNI1, MBNL1, AADACL3, RDH13, TNNI3, BMP2, Wfdc8, PPP1CC2 and MOV10L1 may have left deep marks on the genome during long-term domestication and evolution and may be responsible for the productive and reproductive performance in the Merino and Sunit sheep. These genes have played an important role in the evolution of selection in the three breeds. It is expected that the selected candidate genes will provide some insights for future sheep germplasm mining and foreign introductions.

Effects of common full-sib families on accuracy of genomic prediction for tagging weight in striped catfish Pangasianodon hypophthalmus.

Common full-sib families (c 2 ) make up a substantial proportion of total phenotypic variation in traits of commercial importance in aquaculture species and omission or inclusion of the c 2 resulted in possible changes in genetic parameter estimates and re-ranking of estimated breeding values. However, the impacts of common full-sib families on accuracy of genomic prediction for commercial traits of economic importance are not well known in many species, including aquatic animals. This research explored the impacts of common full-sib families on accuracy of genomic prediction for tagging weight in a population of striped catfish comprising 11,918 fish traced back to the base population (four generations), in which 560 individuals had genotype records of 14,154 SNPs. Our single step genomic best linear unbiased prediction (ssGLBUP) showed that the accuracy of genomic prediction for tagging weight was reduced by 96.5%-130.3% when the common full-sib families were included in statistical models. The reduction in the prediction accuracy was to a smaller extent in multivariate analysis than in univariate models. Imputation of missing genotypes somewhat reduced the upward biases in the prediction accuracy for tagging weight. It is therefore suggested that genomic evaluation models for traits recorded during the early phase of growth development should account for the common full-sib families to minimise possible biases in the accuracy of genomic prediction and hence, selection response.

The impact of genotyping strategies and statistical models on accuracy of genomic prediction for survival in pigs

BackgroundSurvival from birth to slaughter is an important economic trait in commercial pig productions. Increasing survival can improve both economic efficiency and animal welfare. The aim of this study is to explore the impact of genotyping strategies and statistical models on the accuracy of genomic prediction for survival in pigs during the total growing period from birth to slaughter. ResultsWe simulated pig populations with different direct and maternal heritabilities and used a linear mixed model, a logit model, and a probit model to predict genomic breeding values of pig survival based on data of individual survival records with binary outcomes (0, 1). The results show that in the case of only alive animals having genotype data, unbiased genomic predictions can be achieved when using variances estimated from pedigree-based model. Models using genomic information achieved up to 59.2% higher accuracy of estimated breeding value compared to pedigree-based model, dependent on genotyping scenarios. The scenario of genotyping all individuals, both dead and alive individuals, obtained the highest accuracy. When an equal number of individuals (80%) were genotyped, random sample of individuals with genotypes achieved higher accuracy than only alive individuals with genotypes. The linear model, logit model and probit model achieved similar accuracy.ConclusionsOur conclusion is that genomic prediction of pig survival is feasible in the situation that only alive pigs have genotypes, but genomic information of dead individuals can increase accuracy of genomic prediction by 2.06% to 6.04%.

Is there sufficient genetic variation to breed Elsenburg Merino sheep with shorter tails?

Context Breech strike compromises wool production and welfare of Merinos. Long tails contribute to the formation of dags, increasing the risk of sheep attracting gravid blowfly females. Tail-docking is popular globally, as it reduces the incidence of dags. Breeding for a reduced tail length is a more socially accepted measure to replace tail-docking as a management strategy, since stronger legislation for animal welfare is expected. Aim The study used historic data on tail length (TL), birth weight (BW) and bodyweight at docking (DW) to estimate genetic and environmental parameters for these traits in a well known South African resource flock. Methods Merino lambs born from 2016 to 2021 (except for 2020 due to Covid-19) of the Elsenburg Merino flock were recorded for TL, BW and DW. The flock was separated by divergent selection for and against a number of lambs weaned per ewe mated in a High (H) and a Low (L) line. Fixed effects included birth year, sex, selection line, dam age and birth type. ASReml was used to analyse the fixed effects so as to obtain an operational model, before adding the random direct genetic (h2), maternal genetic (m2) and maternal permanent environmental (c2) effects. Results H-line lambs were heavier at birth and tail-docking, with longer tails than those of L-line contemporaries (all P &lt; 0.01). The line difference in TL seemed to be size-dependent, as it was eliminated by adding DW as a covariate to the analysis. The same trend was observed for sex, dam age and birth type. TL was thus affected (P &lt; 0.01) only by birth year in the latter analysis. Regressions of TL on age at tail-docking and DW were highly significant (P &lt; 0.01). Single-trait estimates of h2 were 0.26 for BW, 0.06 for DW, and 0.30 for TL. TL remained heritable at 0.38 in the analysis including DW as a covariate. Including m2 improved the random-effects model for TL (0.08) and DW (0.20). TL and DW were genetically correlated (rG = 0.47 and rM = 0.70). Conclusions TL was moderately heritable, with small m2 and non-significant c2 effects. It will be possible to directly select for TL. However, selection for shorter tails will reduce size if breeding values are not adjusted for DW as a covariate. Implications Further studies on the genetic basis of TL as well as its genetic correlations with other traits of economic importance are warranted.

RNA-sequencing Reveals Differentially Expressed Genes of Laying Hens Fed Baihu Decoction Under Heat Shock.

Egg production, an important economic trait in the poultry industry, is sensitive to heat stress. The hypothalamus is a crucial center for thermoregulation by detecting temperature changes and regulating the autonomic nervous system in poultry. Baihu decoction (BH), which contains four ingredients (Rhizoma Anemarrhenae, Gypsum Fibrosum, Radix Glycyrrhizae, and Semen Oryzae Nonglutinosae), is a traditional Chinese medicinal formula for clearing heat. Our study aimed to investigate the changes in gene transcription levels in the hypothalamus of laying hens treated with heat stress with and without BH using RNA sequencing. A total of 223 differentially expressed genes (DEGs) were identified in the heat-treated group compared with the control group and 613 DEGs were identified in the BH group compared with the heat-treated group. Heat shock led to significant changes in the expression of multiple genes involved in the "neuroactive ligand-receptor interaction" pathway. Moreover, feeding BH led to significant upregulation in the expression of eight genes encoding heat shock proteins (HSPs), which were highlighted as candidates to control the "protein processing in the endoplasmic reticulum (ER)" pathway. These results provide the novel insight that BH responds to heat stress by participating in regulation of the ER signaling pathway and HSPs expression.

Comparative metabolomics analysis shows key metabolites as potential biomarkers for selection of beef fat colour

Context Fat colour is one of the most important economic traits in the marketing of beef. There are many factors that affect fat colour, such as breed, age, diet and gender. Fat colour is observed in different ranges of colours, including white, yellow and brown. The main issue with improving fat colour is that consumer preferences of fat colour vary across the globe. Therefore, investigating the metabolic mechanisms of fat colour may provide new biomarkers for phenotyping, so as to develop effective selection strategies to achieve the locally desired fat colour. Aims This study aimed to perform a comparative metabolic analysis between white and yellow fat from crossbred cattle so as to identify potential biomarkers for the selection of fat colour and to better understand the metabolism of white and yellow fat depots. Methods Carcass samples of subcutaneous fat were collected from crossbred cattle (Simmental × Mongolian cattle) and scored for fat colour. Liquid chromatography–mass spectrophotometry analysis of extracted metabolites from the subcutaneous fat of six animals with white fat and six animals with yellow fat was performed. Key results The comparison between metabolites of white and yellow fat colour samples indicated that there were five categories of 235 significant metabolites, which included hydrocarbons, lipids and lipid-like molecules, organic acids and their derivatives, organic oxygen compounds and organoheterocyclic compounds. The principal-component analysis illustrated that yellow and white fat samples can be classified in groups; however, the metabolites of white fat samples showed greater variation than those in the yellow fat. In the white fat, there were 163 metabolites that had a higher relative abundance than in yellow fat and 72 that had a lower relative abundance than in yellow fat. 3-Hydroxyoctanoic acid, anethofuran, 9,10-DiHODE, furanoeremophilane, pregeijerene, N-glycolylneuraminic acid, and glycocholic acid were identified as the metabolites that differed the most in abundance between the white and yellow fat samples. Conclusions This study has provided insights into the metabolic differences between white and yellow fat depots and identified key metabolites associated with beef fat colour. Implications This study has provided potential biomarkers that may be useful for selection of beef fat colour in live animals.

Progress, adaptability and stability of soybean grain yield and grain quality in conventionally created elite lines

The objective of this study was to determine the progress in grain yield and grain quality accomplished with conventional breeding methods, as well as to identify stable, widely or specifically adapted genotypes under central European growing conditions. Recently developed soybean elite lines of maturity groups (MGs) 00, 0 and I were compared with commercial cultivars (standards) in comparative field tests during three consecutive years (2018-2020) in Osijek, Croatia. The ANOVA results showed significant genotype, environment, and genotype-by-environment interaction effects. There was a significant improvement in productivity and quality in comparison to standards, while stability parameters for tested traits indicated there are stable and mostly specifically adaptable elite lines. Improvement of the domestic gene pool and high agronomic performances of elite lines stable in most important economic traits will considerably contribute to increasing and improving soybean production in central Europe.

PERFORMANCE OF KARADI SHEEP IN KURDISTAN REGION/IRAQ: A REVIEW

The Karadi sheep which comprises about 18-20% of the country sheep population is native to the northern mountain villages and undulating dry-farming plains of Kurdistan region. Rams and ewes are polled, and it is fat tailed animal with an excessively large tail that ends in a thin nonfat terminal extended beyond the fat lobs. The sheep are white with black open face and pendulous ear. The black color often extends to the shoulders and other parts of the body. All Iraqi sheep including Awassi, Arabi and Karadi were exposed over a long period of time to the rigorous and sever semi-dry condition, drought, feed shortage and prevailing disease. Hence their adaptation to the conditions of the country was at the expend of important economic traits. Karadi sheep is hardy with potentials for improvement, their weight and milk display over whelming ranges. In addition, hormonal treatment have improved their reproduction performance, as well as crossing them with other native and exotic breeds is promising. Nevertheless, this breed is not well characterized and much work is needed to explore the potential of this breed for economic traits.

Integrated Transcriptomics Profiling in Chahua and Digao Chickens' Breast for Assessment Molecular Mechanism of Meat Quality Traits.

Meat quality traits are an important economic trait and remain a major argument, from the producer to the consumer. However, there are a few candidate genes and pathways of chicken meat quality traits that were reported for chicken molecular breeding. The purpose of the present study is to identify the candidate genes and pathways associated with meat quality underlying variations in meat quality. Hence, transcriptome profiles of breast tissue in commercial Digao (DG, 5 male) and Chahua (CH, 5 male) native chicken breeds were analyzed at the age of 100 days. The results found 3525 differentially expressed genes (DEGs) in CH compared to DG with adjusted p-values of ≤0.05 and log2FC ≥ 0.1 FDR ≤ 0.05. Functional analysis of GO showed that the DEGs are mainly involved in the two types of processes of meat quality, such as positive regulation of the metabolic process, extracellular structure organization, collagen trimer, cellular amino acid metabolic process, cellular amino acid catabolic process, and heme binding. Functional analysis of KEGG showed that the DEGs are mainly involved in the two types of processes of meat quality, such as oxidative phosphorylation, carbon metabolism, valine, leucine, and isoleucine degradation, and fatty acid degradation. Many of the DEGs are well known to be related to meat quality, such as COL28A1, COL1A2, MB, HBAD, HBA1, ACACA, ACADL, ACSL1, ATP8A1, CAV1, FADS2, FASN, DCN, CHCHD10, AGXT2, ALDH3A2, and MORN4. Therefore, the current study detected multiple pathways and genes that could be involved in the control of the meat quality traits of chickens. These findings should be used as an essential resource to improve the accuracy of selection for meat traits in chickens using marker-assisted selection based on differentially expressed genes.

Genome-Wide Association Study Revealed the Effect of rs312715211 in ZNF652 Gene on Abdominal Fat Percentage of Chickens.

Abdominal fat percentage (AFP) is an important economic trait in chickens. Intensive growth selection has led to the over-deposition of abdominal fat in chickens, but the genetic basis of AFP is not yet clear. Using 520 female individuals from selection and control lines of Jingxing yellow chicken, we investigated the genetic basis of AFP using a genome-wide association study (GWAS) and fixation indices (FST). A 0.15 MB region associated with AFP was located on chromosome 27 and included nine significant single nucleotide polymorphisms (SNPs), which could account for 3.34-5.58% of the phenotypic variation. In addition, the π value, genotype frequency, and dual-luciferase results identified SNP rs312715211 in the intron region of ZNF652 as the key variant. The wild genotype was associated with lower AFP and abdominal fat weight (AFW), but higher body weight (BW). Finally, annotated genes based on the top 1% SNPs were used to investigate the physiological function of ZNF652. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis suggested that ZNF652 may reduce AFW and BW in broilers through the TGF-β1/SMad2/3 and MAPK/FoxO pathways via EGFR and TGFB1. Our findings elucidated the genetic basis of chicken AFP, rs312715211 on the ZNF652 gene, which can affect BW and AFW and was the key variant associated with AFP. These data provide new insight into the genetic mechanism underlying AF deposition in chickens and could be beneficial in breeding chickens for AF.

Detection of polymorphism in growth differentiation factor 9 gene (GDF9) Exon1 and its association with litter size in local Iraqi goats

Litter size is one of the most important economic traits in goats. Growth Differential Factor 9 (GDF9) Gene is suggested as a functional candidate for fertility, fecundity and twining rate. This study was performed to identify SNPs in exon1 of the GDF9 gene and their association with fertility traits in local Iraqi goats. The exon 1 of GDF9 was sequenced, and the SNP (Single nucleotide polymorphism ) was determined in 36 local Iraqi goats. Then the association analyses between polymorphic locals of GDF9 and litter size were performed using the chi-square analysis procedure. The result shows that mutation (C 1902 G) was significantly associated with litter size in local Iraqi goats and the location of C1902 G mutation with three genotypes CC, CG and GG. A significant effect was found for birth weight, weaning weight and twin ratio, where the homozygous dominant genotype outperformed CC. A significant impact was seen for fertility and mortality, where CC topped CG and GG in fertility percentage and superiority of CG over CC and GG in mortality rate. The results preliminarily demonstrated that GDF9 was a critical gene affecting the fecundity of local Iraqi goats and that (C 1902 G) could be a potential genetic marker. Keywords: GDF9 gene, litter size, polymorphism, Iraqi goats