Diversidad genética y estructura de población de cabras autóctonas nigerianas usando marcadores microsatélites DNA

Genetic Diversity and Relationship Among Algerian, Nigerian, and Turkish Goat Breeds Using Microsatellite Markers

BACKGROUND

This study was conducted to identify genetic diversity among goat breeds in Algeria, Türkiye, and Nigeria, which is believed to have arisen due to historical influences, trade networks, and environmental adaptations, using 12 microsatellite markers. Additionally, the study provided insights into the population structure and kinship relationships among the breeds.

METHODS

The animal material of the study consisted of 514 goats from eight breeds: four Algerian (n = 224), two Turkish (n = 140), and two Nigerian (n = 150) native goat breeds. The quality and quantity control of DNA obtained from blood samples was determined using the Nanodrop 2000 device. In the study, 12 microsatellite markers were used. Capillary electrophoresis was used to separate polymerase chain reaction (PCR) fragments labeled with fluorescent dye in the Beckman Coulter GeXP Genetic Analyzer. Statistical analyses were used to calculate molecular genetic parameters, F-statistics, and genetic distances. Factorial correspondence analysis, structure analysis, and dendrogram construction were used to explore population structure.

RESULTS

The study used microsatellite markers to analyze genetic diversity in various breeds, revealing 149 alleles with a mean of 12.41 per locus. Positive inbreeding coefficient within subpopulations (FIS) values indicated a heterozygote deficiency, suggesting potential breeding strategies. Population structure analyses revealed distinct genetic clusters and relationships, providing insights into genetic variation within populations.

CONCLUSION

The study provides a detailed analysis of goat populations in Algeria, Türkiye, and Nigeria, revealing the presence of heterozygote deficiency and the need for strategic breeding interventions to preserve genetic diversity. The findings also reveal distinct genetic clusters and relationships with historical influences, particularly the role of the Mediterranean Sea, adding depth to our understanding. The research offers practical guidance for the sustainable management of these valuable genetic resources, emphasizing adaptive strategies to ensure the resilience and adaptability of goat populations. The findings are crucial for informed decision-making in conserving and utilizing diverse livestock breeds, urging further exploration of goat populations' genetic landscapes.

Single nucleotide polymorphisms (SNPs) in the open reading frame (ORF) of prion protein gene (PRNP) in Nigerian livestock species

BACKGROUND

Prion diseases, also known as transmissible spongiform encephalopathies (TSEs) remain one of the deleterious disorders, which have affected several animal species. Polymorphism of the prion protein (PRNP) gene majorly determines the susceptibility of animals to TSEs. However, only limited studies have examined the variation in PRNP gene in different Nigerian livestock species. Thus, this study aimed to identify the polymorphism of PRNP gene in Nigerian livestock species (including camel, dog, horse, goat, and sheep). We sequenced the open reading frame (ORF) of 65 camels, 31 village dogs and 12 horses from Nigeria and compared with PRNP sequences of 886 individuals retrieved from public databases.

RESULTS

All the 994 individuals were assigned into 162 haplotypes. The sheep had the highest number of haplotypes (n = 54), and the camel had the lowest (n = 7). Phylogenetic tree further confirmed clustering of Nigerian individuals into their various species. We detected five non-synonymous SNPs of PRNP comprising of G9A, G10A, C11G, G12C, and T669C shared by all Nigerian livestock species and were in Hardy-Weinberg Equilibrium (HWE). The amino acid changes in these five non-synonymous SNP were all "benign" via Polyphen-2 program. Three SNPs G34C, T699C, and C738G occurred only in Nigerian dogs while C16G, G502A, G503A, and C681A in Nigerian horse. In addition, C50T was detected only in goats and sheep.

CONCLUSION

Our study serves as the first to simultaneously investigate the polymorphism of PRNP gene in Nigerian livestock species and provides relevant information that could be adopted in programs targeted at breeding for prion diseases resistance.

Whole-genome resource sequences of 57 indigenous Ethiopian goats

Domestic goats are distributed worldwide, with approximately 35% of the one billion world goat population occurring in Africa. Ethiopia has 52.5 million goats, ~99.9% of which are considered indigenous landraces deriving from animals introduced to the Horn of Africa in the distant past by nomadic herders. They have continued to be managed by smallholder farmers and semi-mobile pastoralists throughout the region. We report here 57 goat genomes from 12 Ethiopian goat populations sampled from different agro-climates. The data were generated through sequencing DNA samples on the Illumina NovaSeq 6000 platform at a mean depth of 9.71x and 150 bp pair-end reads. In total, ~2 terabytes of raw data were generated, and 99.8% of the clean reads mapped successfully against the goat reference genome assembly at a coverage of 99.6%. About 24.76 million SNPs were generated. These SNPs can be used to study the population structure and genome dynamics of goats at the country, regional, and global levels to shed light on the species' evolutionary trajectory.

Scrapie-associated polymorphisms of the prion protein gene (PRNP) in Nigerian native goats

Scrapie is a fatal prion protein disease stiffly associated with single nucleotide polymorphism (SNPs) of the prion protein gene (PRNP). The prevalence of this deadly disease has been reported in small ruminants, including goats. The Nigerian goats are hardy, trypano-tolerant, and contribute to the protein intake of the increasing population. Although scrapie has been reported in Nigerian goats, there is no study on the polymorphism of the PRNP gene. Herein, we evaluated the genetic and allele distributions of PRNP polymorphism in 132 Nigerian goats and compared them with publicly available studies on scrapie-affected goats. We utilized Polyphen-2, PROVEAN and AMYCO programs to examine structural variations produced by the non-synonymous SNPs. Our study revealed 29 SNPs in Nigerian goats, of which 14 were non-synonymous, and 23 were novel. There were significant differences (P < 0.001) in the allele frequencies of PRNP codons 139, 146, 154 and 193 in Nigerian goats compared with scrapie-affected goats, except for Northern Italian goats at codon 154. Based on the prediction by Polyphen-2, R139S and N146S were 'benign', R154H was 'probably damaging', and T193I was 'possibly damaging'. In contrast, PROVEAN predicted 'neutral' for all non-synonymous SNPs, while AMYCO showed a similar amyloid propensity of PRNP for resistant haplotype and two haplotypes of Nigerian goats. Our study is the first to investigate the polymorphism of scrapie-related genes in Nigerian goats.

Genetic parameters for somatic cell score, milk yield and type traits in Nigerian Dwarf goats

Objective

This study was conducted to estimate multi-trait genetic parameters for somatic cell score (SCS), milk yield and type traits in Nigerian Dwarf (ND) goats from the United States.

Methods

Data from 1,041 ND goats in the United States with kiddings in 95 herds were used to estimate multi-trait genetic parameters for SCS, milk (MILK), fat (FAT), and protein (PROT) yields, and 14 type traits. An 18-trait mixed linear animal model for lactation mean SCS (Log₂), MILK, FAT, PROT, and 14 type traits was applied. A factor analytic approach (FA1) in ASReml software was used to obtain convergence.

Results

Averages for SCS were low (2.85±1.29 Log₂), and were 314±110.6, 20.9±7.4, and 14±4.9 kg, respectively, for MILK, FAT, and PROT. Heritabilities for SCS, MILK, FAT, and PROT were 0.32, 0.16, 0.16, and 0.10, respectively. The highest heritabilities for type traits were for stature (0.72), teat diameter (0.49), and rump width (0.48), and the lowest estimates were for dairyness (0.003) and medial suspensory ligament (0.03). Genetic correlations of SCS with MILK, FAT, and PROT were positive but low (0.25, 0.18, and 0.23, respectively). Genetic and phenotypic correlations between MILK, FAT, and PROT were high and positive (≥0.66). Absolute values of genetic correlations involving SCS with type traits were generally low or no different from zero. Most of the phenotypic correlations involving SCS with type traits were low. No serious unfavorable genetic correlations between milk yield traits and SCS or between milk yield traits or SCS and type traits were found.

Conclusion

Genetic variation exists in the ND breed for most studied traits. The development of selection programs based on these estimates may help accelerate favorable multi-trait genetic changes in this breed.

Molecular Identification of the "Facciuta Della Valnerina" Local Goat Population Reared in the Umbria Region, Italy

Italy holds important genetic resources of small ruminant breeds. By distinguishing goat breeds at the DNA level, certification of products from specific breeds can be valorized. The aim of this study was to establish the genetic identity of Facciuta della Valnerina, a local goat population of Italy, compared with the cosmopolitan breeds, Saanen and Camosciata delle Alpi, reared in the same geographic area. A total of 116 microsatellite alleles ranging from 4 to 13 were detected at 16 loci in the three goat populations/breeds. A total of 23 private alleles with frequencies lower than 0.3 were detected in the Facciuta della Valnerina population. The mean numbers of alleles were 6.67, 4.58, and 4.92 in Facciuta della Valnerina, Camosciata delle Alpi, and Saanen, respectively. The expected heterozygosity ranged from 0.20 to 0.86. Most loci were highly polymorphic and informative (polymorphic information content ≥0.50). Factorial correspondence analysis and principal components analysis revealed very clear separation between Facciuta della Valnerina and the two reference goat breeds. Reducing the number of markers from 16 to 12 (on the basis of polymorphic information content and the number of alleles) still allowed us to distinguish the local population, indicating that microsatellite markers are capable of discriminating local livestock breeds at a low cost.

Leveraging Available Resources and Stakeholder Involvement for Improved Productivity of African Livestock in the Era of Genomic Breeding

The African continent is home to diverse populations of livestock breeds adapted to harsh environmental conditions with more than 70% under traditional systems of management. Animal productivity is less than optimal in most cases and is faced with numerous challenges including limited access to adequate nutrition and disease management, poor institutional capacities and lack of adequate government policies and funding to develop the livestock sector. Africa is home to about 1.3 billion people and with increasing demand for animal proteins by an ever growing human population, the current state of livestock productivity creates a significant yield gap for animal products. Although a greater section of the population, especially those living in rural areas depend largely on livestock for their livelihoods; the potential of the sector remains underutilized and therefore unable to contribute significantly to economic development and social wellbeing of the people. With current advances in livestock management practices, breeding technologies and health management, and with inclusion of all stakeholders, African livestock populations can be sustainably developed to close the animal protein gap that exists in the continent. In particular, advances in gene technologies, and application of genomic breeding in many Western countries has resulted in tremendous gains in traits like milk production with the potential that, implementation of genomic selection and other improved practices (nutrition, healthcare, etc.) can lead to rapid improvement in traits of economic importance in African livestock populations. The African livestock populations in the context of this review are limited to cattle, goat, pig, poultry, and sheep, which are mainly exploited for meat, milk, and eggs. This review examines the current state of livestock productivity in Africa, the main challenges faced by the sector, the role of various stakeholders and discusses in-depth strategies that can enable the application of genomic technologies for rapid improvement of livestock traits of economic importance.

Polymorphisms of caprine GnRHR gene and their association with litter size in West African Dwarf goats

Gonadotropin-releasing hormone receptor (GnRHR) gene is considered a candidate gene for litter size due to its critical role in regulating the activities of hypothalamo-pituitary-gonadal axis which synthesizes and releases gonadotropins. This study was designed to identify mutations within the caprine GnRHR gene and investigate their association with litter size at various parities. Polymorphisms scanning and genotyping of GnRHR gene in West African Dwarf (WAD) goats (n = 226) revealed three single nucleotide polymorphisms (SNPs), one mutation (g.-29T > G) was detected within 5'UTR region while two others (g.48G > A and g.209T > G) were identified in exon 1. Mutation at g.209T > G locus resulted in amino acid change from Methionine to Arginine at position 70 on the polypeptide residue. Based on heterozygosity and polymorphism information content (PIC), WAD goat population diversity at the SNP loci was moderate. Strong linkage disequilibrium (LD) (r² > 0.98) existed among the detected mutations resulting in three observed haplotypes, two (T-G-T and G-A-G) had cumulative frequency of > 97%. The mutation within 5'UTR region of GnRHR gene (g.-29T > G) is novel, being reported in goats for the first time. Association analysis revealed a significant (p < 0.05) association between allele G at g.-29T > G with higher mean litter size for homozygous (GG) mutant does compared with heterozygotes (GT) or homozygotes (TT), while the relationship between SNPs at the two loci detected in exon 1 and litter size was not significant.