Genetic diversity, breed composition and admixture of Kenyan domestic pigs

<div><p>The genetic diversity of African pigs, whether domestic or wild has not been widely studied and there is very limited published information available. Available data suggests that African domestic pigs originate from different domestication centers as opposed to international commercial breeds. We evaluated two domestic pig populations in Western Kenya, in order to characterize the genetic diversity, breed composition and admixture of the pigs in an area known to be endemic for African swine fever (ASF). One of the reasons for characterizing these specific populations is the fact that a proportion of indigenous pigs have tested ASF virus (ASFv) positive but do not present with clinical symptoms of disease indicating some form of tolerance to infection. Pigs were genotyped using either the porcine SNP60 or SNP80 chip. Village pigs were sourced from Busia and Homabay counties in Kenya. Because bush pigs (<i>Potamochoerus larvatus</i>) and warthogs (<i>Phacochoerus spp</i>.) are known to be tolerant to ASFv infection (exhibiting no clinical symptoms despite infection), they were included in the study to assess whether domestic pigs have similar genomic signatures. Additionally, samples representing European wild boar and international commercial breeds were included as references, given their potential contribution to the genetic make-up of the target domestic populations. The data indicate that village pigs in Busia are a non-homogenous admixed population with significant introgression of genes from international commercial breeds. Pigs from Homabay by contrast, represent a homogenous population with a “local indigenous’ composition that is distinct from the international breeds, and clusters more closely with the European wild boar than African wild pigs. Interestingly, village pigs from Busia that tested negative by PCR for ASFv genotype IX, had significantly higher local ancestry (>54%) compared to those testing positive, which contained more commercial breed gene introgression. This may have implication for breed selection and utilization in ASF endemic areas. A genome wide scan detected several regions under preferential selection with signatures for pigs from Busia and Homabay being very distinct. Additionally, there was no similarity in specific genes under selection between the wild pigs and domestic pigs despite having some broad areas under similar selection signatures. These results provide a basis to explore possible genetic determinants underlying tolerance to infection by ASFv genotypes and suggests multiple pathways for genetically mediated ASFv tolerance given the diversity of selection signatures observed among the populations studied.</p></div

Genetic diversity of the indigenous cattle of Kenya, Uganda, Ethiopia and Tanzania using high-density SNP data

Genetic diversity of the indigenous cattle of Kenya, Uganda, Ethiopia and Tanzania using high-density SNP data. The indigenous cattle make a significant contribution to the livelihood of many communities in Ethiopia, Tanzania and other countries in eastern Africa. Here, we identify the genetic structure and the admixture levels of several East African indigenous cattle breeds in Ethiopia and Tanzania. Two ‘groups’ were studied: Indigenous cattle consisting of a number of breeds; and Mpwapwa cattle – a composite breed. A total of 386 individual animals from the two groups were genotyped using the Illumina high-density Bovine SNP chip (778k Panel). Principal component analysis was used to study the genetic structure and admixture levels of the indigenous cattle, and Mpwapwa were estimated using the ADMIXTURE program. All East African indigenous breeds other than the Ankole appear genetically closely related to each other and consist of a mixture of African taurine and indicine signals. Ethiopian indigenous breeds, Fogera, Danakil Harar and Ethiopian Boran show high purity, whereas Ethiopian Central Highland Breed and the Begait samples show significant amounts of European Bos taurus admixture. Tanzanian indigenous cattle, Singida White and Iringa Red, have a high degree of purity while the TALIRI Boran shows some European Bos taurus genetic background. The synthetic Mpwapwa breed had estimated breed proportions of Bos indicus, African Bos taurus and European Bos taurus of 0.82, 0.05 and 0.13 respectively. These results are useful for genetic conservation and genetic improvement programs

Using the community-based breeding program (CBBP) model as a collaborative platform to develop the African Goat Improvement Network—Image collection protocol (AGIN-ICP) with mobile technology for data collection and management of livestock phenotypes

Introduction: The African Goat Improvement Network Image Collection Protocol (AGIN-ICP) is an accessible, easy to use, low-cost procedure to collect phenotypic data via digital images. The AGIN-ICP collects images to extract several phenotype measures including health status indicators (anemia status, age, and weight), body measurements, shapes, and coat color and pattern, from digital images taken with standard digital cameras or mobile devices. This strategy is to quickly survey, record, assess, analyze, and store these data for use in a wide variety of production and sampling conditions.Methods: The work was accomplished as part of the multinational African Goat Improvement Network (AGIN) collaborative and is presented here as a case study in the AGIN collaboration model and working directly with community-based breeding programs (CBBP). It was iteratively developed and tested over 3 years, in 12 countries with over 12,000 images taken.Results and discussion: The AGIN-ICP development is described, and field implementation and the quality of the resulting images for use in image analysis and phenotypic data extraction are iteratively assessed. Digital body measures were validated using the PreciseEdge Image Segmentation Algorithm (PE-ISA) and software showing strong manual to digital body measure Pearson correlation coefficients of height, length, and girth measures (0.931, 0.943, 0.893) respectively. It is critical to note that while none of the very detailed tasks in the AGIN-ICP described here is difficult, every single one of them is even easier to accidentally omit, and the impact of such a mistake could render a sample image, a sampling day’s images, or even an entire sampling trip’s images difficult or unusable for extracting digital phenotypes. Coupled with tissue sampling and genomic testing, it may be useful in the effort to identify and conserve important animal genetic resources and in CBBP genetic improvement programs by providing reliably measured phenotypes with modest cost. Potential users include farmers, animal husbandry officials, veterinarians, regional government or other public health officials, researchers, and others. Based on these results, a final AGIN-ICP is presented, optimizing the costs, ease, and speed of field implementation of the collection method without compromising the quality of the image data collection

Correlation of Particular Bacterial PCR-Denaturing Gradient Gel Electrophoresis Patterns with Bovine Ruminal Fermentation Parameters and Feed Efficiency Traits ▿ †

The influence of rumen microbial structure and functions on host physiology remains poorly understood. This study aimed to investigate the interaction between the ruminal microflora and the host by correlating bacterial diversity with fermentation measurements and feed efficiency traits, including dry matter intake, feed conversion ratio, average daily gain, and residual feed intake, using culture-independent methods. Universal bacterial partial 16S rRNA gene products were amplified from ruminal fluid collected from 58 steers raised under a low-energy diet and were subjected to PCR-denaturing gradient gel electrophoresis (DGGE) analysis. Multivariate statistical analysis was used to relate specific PCR-DGGE bands to various feed efficiency traits and metabolites. Analysis of volatile fatty acid profiles showed that butyrate was positively correlated with daily dry matter intake (P < 0.05) and tended to have higher concentration in inefficient animals (P = 0.10), while isovalerate was associated with residual feed intake (P < 0.05). Our results suggest that particular bacteria and their metabolism in the rumen may contribute to differences in host feed efficiency under a low-energy diet. This is the first study correlating PCR-DGGE bands representing specific bacteria to metabolites in the bovine rumen and to host feed efficiency traits

Genetic diversity, breed composition and admixture of Kenyan domestic pigs

The genetic diversity of African pigs, whether domestic or wild has not been widely studied and there is very limited published information available. Available data suggests that African domestic pigs originate from different domestication centers as opposed to international commercial breeds. We evaluated two domestic pig populations in Western Kenya, in order to characterize the genetic diversity, breed composition and admixture of the pigs in an area known to be endemic for African swine fever (ASF). One of the reasons for characterizing these specific populations is the fact that a proportion of indigenous pigs have tested ASF virus (ASFv) positive but do not present with clinical symptoms of disease indicating some form of tolerance to infection. Pigs were genotyped using either the porcine SNP60 or SNP80 chip. Village pigs were sourced from Busia and Homabay counties in Kenya. Because bush pigs (Potamochoerus larvatus) and warthogs (Phacochoerus spp.) are known to be tolerant to ASFv infection (exhibiting no clinical symptoms despite infection), they were included in the study to assess whether domestic pigs have similar genomic signatures. Additionally, samples representing European wild boar and international commercial breeds were included as references, given their potential contribution to the genetic make-up of the target domestic populations. The data indicate that village pigs in Busia are a non-homogenous admixed population with significant introgression of genes from international commercial breeds. Pigs from Homabay by contrast, represent a homogenous population with a “local indigenous’ composition that is distinct from the international breeds, and clusters more closely with the European wild boar than African wild pigs. Interestingly, village pigs from Busia that tested negative by PCR for ASFv genotype IX, had significantly higher local ancestry (>54%) compared to those testing positive, which contained more commercial breed gene introgression. This may have implication for breed selection and utilization in ASF endemic areas. A genome wide scan detected several regions under preferential selection with signatures for pigs from Busia and Homabay being very distinct. Additionally, there was no similarity in specific genes under selection between the wild pigs and domestic pigs despite having some broad areas under similar selection signatures. These results provide a basis to explore possible genetic determinants underlying tolerance to infection by ASFv genotypes and suggests multiple pathways for genetically mediated ASFv tolerance given the diversity of selection signatures observed among the populations studied.This article is published as Mujibi, Fidalis Denis, Edward Okoth, Evans K. Cheruiyot, Cynthia Onzere, Richard P. Bishop, Eric M. Fèvre, Lian Thomas, Charles Masembe, Graham Plastow, and Max Rothschild. "Genetic diversity, breed composition and admixture of Kenyan domestic pigs." PloS one 13, no. 1 (2018): e0190080. doi: 10.1371/journal.pone.0190080. </p

The number of pigs that tested ASFv positive and negative given their local pig ancestry proportions.

<p>The number of pigs that tested ASFv positive and negative given their local pig ancestry proportions.</p

Observed heterozygosity (Mean ± SD) in various pig groups evaluated.

<p>Observed heterozygosity (Mean ± SD) in various pig groups evaluated.</p

Sample populations, source project and sample utility in the project.

<p>Sample populations, source project and sample utility in the project.</p

Cross validation plot indicating the model suitability as the number of putative populations (K) increases.

<p>Cross validation plot indicating the model suitability as the number of putative populations (K) increases.</p