Hardy-Weinberg Disequilibrium Research Articles

Polymorphisms of the HRG, FETUB, and GUCY1A1 genes and their association with litter size in sheep

Abstract. Litter size is one of the key factors affecting the efficiency of sheep breeding, and previous studies found that the HRG, FETUB, and GUCY1A1 genes were closely related to litter size in sheep. This experiment aims to explore the polymorphisms of the g.405442728A>G locus of the HRG gene, the g.421655951C>T locus of the FETUB gene, and the g.414050897G>C locus of the GUCY1A1 gene and their association with sheep litter size. The MassARRAY® single-nucleotide polymorphism (SNP) genotyping technique was used to detect the polymorphisms of these loci in five sheep breeds, i.e., Small-tailed Han sheep, Hu sheep, Cele black sheep, Sunite sheep, and Bamei mutton sheep. In addition, the association between the polymorphisms of these genes and the litter size of Small-tailed Han sheep was also analyzed. The results showed that the g.405442728A>G locus of the HRG gene was moderately polymorphic (0.25 < PIC <0.5) in both monotocous and polytocous sheep breeds; the g.421655951C>T locus of the FETUB gene was lowly polymorphic (PIC <0.25) in five sheep breeds; the g.414050897G>C locus of GUCY1A1 showed moderately polymorphism in Small-tailed Han sheep (0.25 ≤ PIC <0.5) and low polymorphism in four other sheep breeds (PIC <0.25). The chi-squared test results showed that the g.405442728A>G locus of the HRG gene was in the Hardy–Weinberg equilibrium state in five sheep breeds (P>0.05). The g.421655951 C>T locus of the FETUB gene and the g.414050897G>C locus of the GUCY1A1 gene were in the Hardy–Weinberg equilibrium state in Small-tailed Han sheep (P>0.05) and in the Hardy–Weinberg disequilibrium state in other sheep breeds (P<0.05). The association analysis showed that the g.405442728A>G locus of the HRG gene and the g.421655951C>T locus of the FETUB gene had a significant impact on the litter size of sheep (P<0.05), while the g.414050897G>C locus of the GUCY1A1 gene had no significant impact on the litter size (P>0.05). In summary, the HRG gene and the FETUB gene can be used as potential molecular markers for the selection of the litter size in sheep.

Investigating growth associated genomic short tandem repeats (STRs) in a resource population generated through molecular breeding of RIR chicken

The long-term selection based on phenotypes causes loss of variation in performance traits and slows down the genetic progress per generation in the population; genomic selection could restore the variability along with faster genetic progress. Genomic short tandem repeats (STRs) in a resource population of RIR chicken were explored investigating randomly selected 114 pedigreed chicks. Alleles separated through 3.4% MetaPhor agarose gel electrophoresis at ten STR loci, and data recorded on growth traits were analyzed. Twenty-six alleles were resolved with frequencies of 0.1140–0.7632 and > 38.60% for the most frequent alleles at ten STR loci. The most frequent genotypes appeared with frequency >21.93% at different loci. Polymorphic information contents ranged from 0.2961 (LEI0079) to 0.6716 (LEI0071). Effective number of alleles ranged from 1.5662 (LEI0079) to 3.5836 (LEI0071). Mean FIS statistics revealed overall 21.78% heterozygosity deficit. Average heterozygosity ranged from 0.3630 (LEI0079) to 0.7241 (LEI0071). Chi-square and G-square test showed the population in Hardy-Weinberg disequilibrium at nine loci. Chick weight was significantly influenced by the factor of sire, and body weight traits by sex and hatch factors of the birds coded with STR-genotypes. ADL0328-BB genotype had the highest chick weight. LEI0068-BC and LEI0071-CC genotypes showed maximum 28-weeks body weight. MCW0010-AA genotype had the potential bearing of the highest body weight records at 16, 32, 36 and 40 weeks of age. MCW0058-CC genotype revealed the same at 24 and 28 weeks of age. The study impacts on marker assisted selection program for genetic improvement of growth traits in poultry.

FecB Was Associated with Litter Size and Follows Mendel's Laws of Inheritance When It Transited to Next Generation in Suhu Meat Sheep Breeding Population.

In order to investigate the effect of FecB on litter size and growth and development traits of Suhu meat sheep and the inheritance patterns of FecB between parents and offspring in the population. In this experiment, 2241 sheep from the Suhu meat sheep population were tested for FecB using capillary electrophoresis. We combined the lambing records of 473 ewes, the growth trait records of 881 sheep at both the birth and weaning (2-month-old) stages, and the complete genealogical records of 643 lambs to analysis the distribution of FecB in the Suhu meat sheep breeding population, its effect on litter size of ewes, growth and development of lambs, and the inheritance patterns of FecB. The results showed that there were three genotypes of FecB in the Suhu meat sheep population, namely the AA genotype, AG genotype, and GG genotype. FecB in this population has a moderate polymorphism (0.25 < PIC < 0.5), and deviates from Hardy-Weinberg disequilibrium (p < 0.05). The litter size of GG genotype ewes was significantly higher than that with the AG and AA genotypes (p < 0.01). A Chi-square test showed that the inheritance patterns of FecB follows Mendel's Laws of Inheritance (p > 0.05). An association analysis of different genotypes of FecB with body weight and body size of Suhu meat sheep at birth and weaning revealed that FecB adversely affects the early growth and development of Suhu meat sheep. In summary, FecB can improve the litter size of ewes but it has negative effects on the early growth and survival rate of lambs in sheep. Therefore, FecB test results and feeding management measures should be comprehensively applied to improve the reproductive performance of ewes, the survival rate and production performance of lambs in sheep production, and thus improve the economic benefits of sheep farms.

Correlation of 20 Single-Nucleotide Polymorphisms with Weight and Wool Traits in Alpine Merino Sheep.

SNPs associated with important traits of fine-wool sheep that were previously obtained through genome-wide association analysis screening were verified and analyzed. A total of 20 SNPs related to birth weight, bundle strength, cleaning rate, and fiber diameter were screened using whole-genome resequencing, and the SNPshot assay was used to detect and analyze polymorphisms. This study found that, among the 20 SNPs associated with important traits in Alpine Merino sheep, 8 were monomorphic and 12 were polymorphic, of which 6 showed moderate polymorphisms and 6 showed low polymorphisms. The heterozygosity of the 12 polymorphic loci ranged from 0.10 to 0.49, the effective number of alleles ranged from 1.11 to 1.98, and the polymorphic information content ranged from 0.09 to 0.37. The chi-square test showed that only RHPN2:g.42678119T>G and RALYL:g.90030866A>G were in Hardy-Weinberg disequilibrium (p < 0.05); the other loci were in equilibrium (p > 0.05). These SNPs associated with important traits in Alpine Merino sheep provide a theoretical basis for genomic selection and molecular design breeding.

Effects of Recurrent Selection on Population Structure and Allele Frequencies in the M3S Maize Population

The effects of four cycles of recurrent selection on the allele frequencies of simple sequence repeat (SSR) markers and population structure were examined in the Maksimir 3 Synthetic (M3S) maize population (Zea mays L.). Genotyping of 32 plants from each selection cycle at 38 SSR loci revealed that the mean number of alleles per locus and the mean expected heterozygosity were preserved across selection cycles, indicating the maintenance of sufficient genetic variability in the population required for future genetic gain. The Waples test of selective neutrality revealed that genetic drift was the main force in changing allele frequencies in the population. The proportion of selectively non-neutral loci in single cycles of selection varied between 16% and 37%. Some non-neutral loci shared the same genomic locations with previously published QTLs controlling important agronomic traits. An analysis of molecular variance revealed that 5.6% of the genetic variation occurred among and 94.4% within cycle populations. Between 5% and 29% of loci were found to be in a significant Hardy–Weinberg (HW) disequilibrium, with the majority showing an excess of homozygosity. The excess of homozygosity at several loci was highly consistent across cycle populations, suggesting positive assortative mating as a possible cause of the observed HW disequilibrium. Linkage disequilibrium (LD) tests revealed that the M3S population was essentially in linkage equilibrium. The proportion of pairs of loci in significant LD varied from 0.1% to 1.8% across selection cycles, probably due to the effects of genetic drift and epistatic selection.

Structure and genetic variability of the Costa Rican Paso horse

The Costa Rican Paso Horse (CPC) is a breed developed in Costa Rica. The objectives were to estimate the genetic structure and evaluate the levels of genetic variability of the population. The genotypes of 14 microsatellites in 3654 records (2052 females and 1602 males) were analyzed. Expected (He) and observed (Ho) heterozygosity, polymorphic information content (CIP), fixation index (FIS), Shannon index, as well as Hardy-Weinberg disequilibrium (DHW) were evaluated. Kinship relationships (Rij) were estimated throughout the entire population. The effective population size (Ne) was calculated, alternating allele frequencies less than 0.05, 0.02 and 0.01. The Bayesian clustering study was carried out to infer how many lines are appropriate from the analysis of genotypes using multiple loci. The number of alleles per locus ranged from 7 to 17, with an average value of 9.6; nine loci presented DHW (P < 0.05); two loci presented negative FIS values, the same as Ho > He; the average of CIP, Ho and He was 0.254, 0.756 and 0.785, respectively. At the 12 loci where He > Ho, the differences ranged from 0.002 to 0.341 (0.036 on average). For Ne, the estimates were 201.9, 230.1, and 241.5. In the Rij, 54.86% of the estimates were in the interval of 0.01 to 77.7%. The number of lines that define the population corresponds to three, with an approximate composition of 33.1%, 32.4% and 34.5%, respectively. The CPC, as a subdivided population with DHW and a reduction in heterozygotes may be associated with possible Wahlund effects. Keywords: Wahlund effect, equines, genetic markers, synthetic breed, Hardy Weinberg.

Are scattered microsatellites weak chromosomal markers? Guided mapping reveals new insights into Trachelyopterus (Siluriformes: Auchenipteridae) diversity.

The scattered distribution pattern of microsatellites is a challenging problem in fish cytogenetics. This type of array hinders the identification of useful patterns and the comparison between species, often resulting in over-limited interpretations that only label it as "scattered" or "widely distributed". However, several studies have shown that the distribution pattern of microsatellites is non-random. Thus, here we tested whether a scattered microsatellite could have distinct distribution patterns on homeologous chromosomes of closely related species. The clustered sites of 18S and 5S rDNA, U2 snRNA and H3/H4 histone genes were used as a guide to compare the (GATA)n microsatellite distribution pattern on the homeologous chromosomes of six Trachelyopterus species: T. coriaceus and Trachelyopterus aff. galeatus from the Araguaia River basin; T. striatulus, T. galeatus and T. porosus from the Amazonas River basin; and Trachelyopterus aff. coriaceus from the Paraguay River basin. Most species had similar patterns of the (GATA)n microsatellite in the histone genes and 5S rDNA carriers. However, we have found a chromosomal polymorphism of the (GATA)n sequence in the 18S rDNA carriers of Trachelyopterus galeatus, which is in Hard-Weinberg equilibrium and possibly originated through amplification events; and a chromosome polymorphism in Trachelyopterus aff. galeatus, which combined with an inversion polymorphism of the U2 snRNA in the same chromosome pair resulted in six possible cytotypes, which are in Hardy-Weinberg disequilibrium. Therefore, comparing the distribution pattern on homeologous chromosomes across the species, using gene clusters as a guide to identify it, seems to be an effective way to further the analysis of scattered microsatellites in fish cytogenetics.

Leveraging Hardy–Weinberg disequilibrium for association testing in case-control studies

Leveraging Hardy–Weinberg disequilibrium for association testing in case-control studies

Genetic characterisation of indigenous duck of Tripura state in India using microsatellite markers.

Exploring genetic variability by microsatellite markers is essential for genetic improvement, preservation of indigenous germplasm and production of high-quality offspring. Lack of information on microsatellite profiling of Indian indigenous ducks (Tripura state) has stoked curiosity in this work. Genomic DNA samples from randomly selected 36 native ducks were analysed at 25 duck-specific microsatellite loci. Alleles were separated through 3.4% MetaPhore™ agarose gel electrophoresis. Allele sizes were determined using Image Lab 6 software of GelDoc™ EZ System. Allelic data were analysed by POPGENE version 1.31. Total 112 alleles were resolved and all the loci were found polymorphic with 2 to 15 alleles across the loci. Average number of allele (Na) was 4.480 ± 0.659. Allele sizes and frequencies ranged from 96 to 357bp and 0.014 to 0.819, respectively. Average heterozygosity of Nei, effective number (Ne) of alleles and Shannon's information index (I) were 0.617 ± 0.036, 3.538 ± 0.527 and 1.184 ± 0.112, respectively. The estimates of Ne were less than the Na at all the loci, indicating prevalence of heterozygosity. Polymorphic information content (PIC) ranged from 0.252 (CAUD020) to 0.911 (CAUD019) with an average of 0.562 ± 0.040. Sixteen loci were moderate to highly polymorphic and informative (PIC ˃ 0.5). Chi-square and G-square statistics revealed Hardy-Weinberg disequilibrium at all the loci. Moderate to high level of polymorphism of the studied microsatellites indicated that these markers might be helpful for genetic characterisation and adoption of appropriate conservation strategies to exploit optimum genetic potentiality of indigenous ducks of Tripura.

Association between Stearoyl CoA Desaturase (SCD) Gene Polymorphisms and Milk Production in Holstein Cattle Breed

The SCD gene is a significant component of the leptin signaling pathway. The SCD gene has also been suggested as a candidate essential gene that can change the ratio of saturated to unsaturated fatty acids in milk and increase the amount of conjugated linoleic fatty acid, which is thought to have anti-cancer properties. The current research was carried out on Holstein cows to determine the association between SCD (Stearoyl-Coenzyme A Desaturase) gene polymorphism and total milk yield at 305 days (TMY305) and daily milk yield (DMY). The polymorphism in the SCD gene was identified using the PCR-RFLP technique and the SatI restriction enzyme for genotyping at SNP c.878T&gt;C in the exon 5. The TT, TC, and CC genotype frequencies were 0.21, 0.50, and 0.29 respectively. While the allele frequencies of T and C were 0.46 and 0.54, respectively. According to the Chi-square test results, the SCD/c.878T&gt;C distribution was in Hardy-Weinberg disequilibrium (P&lt;0.05). Statistical analysis indicated a significant association between the SCD gene polymorphism and TMY305 (P&lt;0.05). The TC genotypes showed a higher mean TMY305 compared to the TT and CC genotypes.

Association between the TP53 Arg72Pro Polymorphisms and Gastric Cancer Risk: An Updated Meta-Analysis and Re-Analysis of Systematic Meta-Analyses

Background: A latest Meta-analysis on TP53 Arg72Pro polymorphism with gastric cancer (GC) risk was published in 2015 including 20 literatures, while our study included 43 studies. Moreover, the results of previously published original studies were inconsistent and the credibility of the significant correlation between the statistical results has been ignored. Therefore, an updated Meta-analysis was conducted to further explore these associations. Objective: To explore whether these two gene polymorphisms are related to the risk, clinical manifestations, and pathological features of GC. Methods: We searched several Chinese and English databases. The crude odds ratio (OR) with 95% confidence interval (CI) was used to evaluate the correlation. In addition, false positive reporting probability (FPRP), bayesian false discovery probability (BFDP), and Venice criteria were used to assess the reliability of statistically significant correlation. Results: Overall, the TP53 Arg72Pro polymorphism was related to a significantly increased GC risk (AP vs. AA: OR = 1.12, 95% CI = 1.02 - 1.24; PP + AP vs. AA: OR = 1.12, 95% CI = 1.02 - 1.24; P vs. A: OR = 1.07, 95% CI = 1.00 - 1.15). However, after excluding the low quality and Hardy–Weinberg Disequilibrium (HWD) studies, significant changes were found on the TP53 Arg72Pro polymorphism with GC risk in Caucasians (PP vs. AA: OR = 1.48, 95% CI = 1.01 - 2.16) and non-gastric cancer control groups (PP vs. AP + AA: OR = 1.33, 95% CI = 1.07 - 1.64)). However, the above significant results were considered unreliable after being adjusted with Bayesian error detection probability (BFDP) and false positive reporting probability (FPRP). These unreliable results were confirmed again, and no new reliable results were found in the further sensitivity analysis (only studies that met the quality assessment criteria). Conclusions: After considering the quality of the study and the reliability of the results, this Meta-analysis showed that TP53 codon 72 polymorphisms had no significant correlation with GC risk. Because of various confounding factors, the result that these polymorphisms increase GC risk is more likely to be a false positive result.

Dynamics of Panstrongylus megistus infestation, the primary vector of Trypanosoma cruzi in Minas Gerais, Brazil

Panstrongylus megistus is considered one of the primary species of epidemiological importance for the transmission of Chagas disease in Brazil due to its wide geographical distribution throughout the national territory, good ability to invade and colonize houses, and high rates of natural infection by the Trypanosoma cruzi. The importance of this species in Minas Gerais has been recognized since the 80s. It is responsible for the high prevalence rates of Chagas disease in the west of the state. Studies conducted in the municipality of Jaboticatubas show that P. megistus is still the most captured vector in the region, even after 40 years of uninterrupted actions of the Chagas Disease Control Program in the municipality. Despite the importance of the species, its population dynamics is little studied. Consequently, crucial genetic information such as genetic diversity and gene flow among environments have not been well characterized yet. In this context, this work presents a population genetic analysis at the microgeographic level using microsatellite markers in samples of P. megistus obtained from Jaboticatubas to better understand the infestation dynamics of the primary vector species of T. cruzi in the region. The observed and expected heterozygosity ranged from 0.26 to 0.47 and 0.47 to 0.65, respectively. Most loci presented Hardy-Weinberg disequilibrium due to the excess of homozygotes. The pairwise Fst ranged from 0.05 to 0.35, with the p value significant for all comparisons, indicating the absence of gene flow between them. The values of Fis found ranged from 0.25 to 0.52, all values of p ≤ 0.05, probably due to structured populations, inbreeding, or null alleles. The results suggest an extended stay of this species in the colonized environments, with rare dispersal to other locations. Such results differ from that observed for Triatoma brasiliensis and Triatoma dimidiata, species that present constant movement, even after colonization of the artificial environment, and are similar to the behavior of Triatoma infestans. Thus, the study reinforces the importance of continuous entomological surveillance in the areas of occurrence of P. megistus to avoid the installation and formation of new foci of household infestation in the region.

Assessment of the association of the MOGAT1 and MOGAT3 gene with growth traits in different growth stages in Holstein calves.

The members of the monoacylglycerol acyltransferase (MOGAT) family are essential candidate genes that influence economic traits associated with triglyceride synthesis, dietary fat absorption, and storage in livestock. In addition, the MOGAT gene family may also play an essential function in human polygenic diseases, like type 2 diabetes and obesity. The present study was conducted on Holstein calves to find the association between MOGAT1, MOGAT3/g.A229G, and MOGAT3/g.G1627A and growth traits. The polymerase chain reaction–restriction fragment length polymorphism (PCR-RFLP) method was performed for genotyping the MOGAT1, MOGAT3/g.A229G, and MOGAT3/g.G1627A genes' locus using the TaqI, MspI, and BsuRI restriction enzyme. The allele frequency of A and G of the MOGAT1 locus was 0.79 and 0.21, respectively, while the genotype frequency was 0.65, 0.28, and 0.07 for AA, AG, and GG, respectively. While the allele and genotype frequencies of the MOGAT3/g.A229G locus were 00.57(), 0.43(), 0.35(), 0.45(), and 0.20(), the allele and genotype frequencies of the MOGAT3/g.G1627A locus were 0.49(), 0.51(), 0.25(), 0.49(), and 0.26(). Chi-square analysis showed that MOGAT3/g.G1627A distribution was at the Hardy–Weinberg disequilibrium (  0.05), and MOGAT1 and MOGAT3/g.A229G distribution was at the Hardy–Weinberg equilibrium (  0.05). In total, two statistical methods (general linear model (GLM) and PROC MIXED) were used to identify an association between gene locus and growth traits. An association analysis showed a statistically significant difference between the MOGAT1 and body weight, body length, and chest circumference, MOGAT3/g.A229G with average daily gain (ADG) and withers height, and MOGAT3/g.G1627A with body weight and body length (  0.05). The results confirmed that the MOGAT1, MOGAT3/g.A229G, and MOGAT3/g.G1627A locus are strong candidate genes that could be considered molecular markers for growth traits in cattle breeding.

Linear Mixed-Effect Models Through the Lens of Hardy-Weinberg Disequilibrium.

For genetic association studies with related individuals, the linear mixed-effect model is the most commonly used method. In this report, we show that contrary to the popular belief, this standard method can be sensitive to departure from Hardy–Weinberg equilibrium (i.e., Hardy–Weinberg disequilibrium) at the causal SNPs in two ways. First, when the trait heritability is treated as a nuisance parameter, although the association test has correct type I error control, the resulting heritability estimate can be biased, often upward, in the presence of Hardy–Weinberg disequilibrium. Second, if the true heritability is used in the linear mixed-effect model, then the corresponding association test can be biased in the presence of Hardy–Weinberg disequilibrium. We provide some analytical insights along with supporting empirical results from simulation and application studies.

Evaluation of Association Studies and an Updated Meta-Analysis of VDR Polymorphisms in Osteoporotic Fracture Risk.

Background: Several studies have examined the association between vitamin D receptor (VDR) polymorphisms and osteoporotic fracture risk; however, the results are not uniform. Furthermore, many new articles have been published, and therefore, an updated meta-analysis was performed to further explore these issues. Objectives: The aim of the study was to investigate the association between VDR, BsmI, ApaI, TaqI, FokI, and Cdx2 polymorphisms and osteoporotic fracture risk. Methods: The odds ratios (ORs) and 95% confidence intervals (CIs) were used to assess the association between VDR BsmI, ApaI, TaqI, FokI, and Cdx2 polymorphisms and the risk of osteoporotic fracture. We also used the false-positive reporting probability (FPRP) test and the Venice criteria to evaluate the credibility of the statistically significant associations. Results: Overall, this study found that the VDR ApaI and BsmI polymorphisms significantly increased the risk of osteoporotic fracture in European countries and America, respectively. However, when sensitivity analysis was performed after excluding low-quality and Hardy–Weinberg disequilibrium (HWD) studies, it was found that only individuals with the double-mutated genotype have an increased risk of osteoporotic fracture in European countries. In addition, when the credibility of the positive results was assessed, it was found that the positive results were not credible. Conclusion: This meta-analysis indicates that there may be no significant association among the polymorphisms of VDR BsmI, ApaI, TaqI, FokI, and Cdx2 and the risk of osteoporotic fracture. The increased risk of osteoporotic fracture is most likely due to false-positive results.

Quantitative Trait Loci Identification by Estimating the Genetic Model based on the Extremal Samples.

Background In genetic association studies with quantitative trait loci (QTL), the association between a candidate genetic marker and the trait of interest is commonly examined by the omnibus F test or by the t-test corresponding to a given genetic model or mode of inheritance. It is known that the t-test with a correct model specification is more powerful than the F test. However, since the underlying genetic model is rarely known in practice, the use of a model-specific t-test may incur substantial power loss. Robust-efficient tests, such as the Maximin Efficiency Robust Test (MERT) and MAX3 have been proposed in the literature.Methods In this paper, we propose a novel two-step robust-efficient approach, namely, the genetic model selection (GMS) method for quantitative trait analysis. GMS selects a genetic model by testing Hardy-Weinberg disequilibrium (HWD) with extremal samples of the population in the first step and then applies the corresponding genetic model-specific t-test in the second step.Results Simulations show that GMS is not only more efficient than MERT and MAX3, but also has comparable power to the optimal t-test when the genetic model is known.Conclusion Application to the data from Alzheimer’s Disease Neuroimaging Initiative (ADNI) cohort demonstrates that the proposed approach can identify meaningful biological SNPs on chromosome 19.

A framework to model a web of linkage disequilibria for natural allotetraploid populations

Abstract Linkage disequilibrium (LD) is an important genetic parameter used to infer the genetic diversity of natural populations and their evolutionary history. Traditionally, LD is defined as the non‐random association of non‐alleles at different loci in gametes for diploids, but has a limited use for polyploids. We formulate a framework to define tetraploid‐specific LD including (a) Hardy–Weinberg disequilibria at each locus, (b) composite digenic disequilibrium, (c) trigenic disequilibrium and (d) composite quadrigenic disequilibrium at different loci. These four types of disequilibria affect population variation singly or jointly through a web. We implement the EM algorithm to estimate each disequilibrium parameter and test its significance in allotetraploid populations. We perform computer simulation to examine the statistical properties of our computational model. Through analysing a population genetic data of allotetraploid switchgrass, we chart the genomic distribution of LD on different chromosomes from which the evolutionary history of switchgrass is inferred, demonstrating the practical usefulness of the model. We have developed a statistical model for LD analysis in allotetraploids. The model can be generalized as a tool to study the population diversity and evolution of polyploid populations.

Do Pharaohs’ cattle still graze the Nile Valley? Genetic characterization of the Egyptian Baladi cattle breed

Egyptian Baladi cattle is one of the few native taurine breeds which remain in the original domestication area of Bos taurus, the Nile Valley (Upper Egypt). Apart from its evolutive relevance, the breed is well-adapted and integrated into the traditional family farming systems, with great potentialities for local sustainable rural development. The diversity and structure of the Baladi population were assessed using 28 genetic microsatellite markers. Within and between-breeds diversity, its relations with other cattle breeds, and an inference on its origin and evolution, were analyzed. Results reported high levels of diversity, with an average number of alleles (Na) of 11.39, observed heterozygosity (Ho) of 0.68, and expected heterozygosity (He) of 0.75. The studied population was in Hardy-Weinberg disequilibrium, which could be ascribed to its internal structure. The comparison between breeds using factorial correspondence analysis, Reynolds genetic distance evaluation, and genetic structure analysis suggested slight influences of Bos indicus. Upper Egypt’s rural communities have preserved the Baladi cattle breed, protecting this historical and biological heritage against the constant and indiscriminate introduction of exotic genetic resources along the history of development of the breed. Developing and implementing conservation and breeding programs is crucial for the preservation and improvement of the breed. HIGHLIGHTS Baladi cattle breed is a well-defined and highly diverse breed. Higher diversity levels are found in northern and central governorates. A clear geographical cluster is formed around the Nile Delta. Baladi cattle may be reminiscent of the ancient ‘pharaoh’ cattle. Assiut’s population acted as the most ancestral population nucleus.

Single Genetic Stock Revealed by Microsatellite Markers Among Wild Populations of Cirrhinus mrigala from Peninsular India

Cirrhinus mrigala (mrigal) is one of the Indian major carps widely cultured in the whole Indian subcontinent. Population genetic structure of this species from Peninsular Rivers of India is lacking. Among DNA markers, microsatellites are excellent tools to evaluate genetic variation of populations. In this study, genetic variation of six peninsular riverine mrigal populations was evaluated using seventeen microsatellite loci. In analyzing 288 samples, the number of alleles ranged from 4 to 27; observed heterozygosity from 0.595 to 1.00, expected heterozygosity from 0.586 to 0.959 and inbreeding coefficient (FIS) ranged from -0.034 to 0.02. Exact test for Hardy Weinberg disequilibrium revealed that one locus was not in equilibrium across the rivers except one. The AMOVA analysis revealed the main source of genetic variation to be within the population (94.54%) than among the populations (5.46%). The Nei’s genetic distance and structure analysis depict river Narmada and Mahi populations are different from the four east coast rivers. The overall Fst (0.05462) data showed moderate differentiation among the six populations. The results of this study provide essential information to resource recovery and help in delineating populations for fishery management. Besides, the data will provide a valuable baseline for further investigations on the geographic distribution of this commercially important fish species.

Genetic evaluation of F2 inbred strain of Swiss albino mice by microsatellite markers

Genetic characterization of F2 inbred Swiss albino mice was done using 11 microsatellites markers (D1Mit15, D2Mit51, D2Mit61, D3Mit15, D3Mit55, D5Mit18, D7Mit323, D8Mit14, D9Mit27, D10Mit180, and D11Mit167). The results indicated that genotypic frequencies at all the loci were in Hardy-Weinberg disequilibrium (P&lt;0.001). Total number of alleles per locus ranged from 3 (D2Mit61, D3Mit15, D8Mit14, D9Mit27, D10Mit180, D11Mit167) to 4 (D1Mit15, D2Mit51, D3Mit55, D5Mit18, D7Mit323), with a mean of 3.45. The numbers of effective alleles ranged between 1.847 and 3.814. The observed heterozygosity (Ho) was maximum for D1Mit15 (0.660) and minimum for D5Mit18 (0.080), with mean of 0.269. The FIS estimates was ranged from 0.0817 (D1Mit15) to 0.8799 (D5Mit18). The average inbreeding coefficient was 0.592, which indicates that parents were more related than expected under random mating. The range of PIC value (from 0.414 to 0.689) for various microsatellite loci was revealing that population under investigation was of high diversity maintaining a multiple allele.