Phenotypic Features and Genetic Characterization of Galla Goats from Selected Regions in Kenya Using Mitochondrial DNA and HSP70 Gene Polymorphisms

Abstract

Galla goats are mainly found in arid and semi-arid regions of Kenya, which are mostly affected by climate change. Indiscriminate crossbreeding has led to the erosion of genetic pool of indigenous goats, which are hardy and better adapted to the local climatic conditions including hot environment as compared to exotic goat breeds. Hot climatic conditions result in heat stress that suppresses productivity and reproducibility. Thermotolerance is therefore an important trait to be considered during breeding. Breeding programmes need to conserve and incorporate desirable traits from the indigenous goats. For this to be accomplished, there must be understanding of the genetic diversity of the indigenous goat population. This study reports on the adaptation and diversity of this indigenous genetic resource. Specifically, the study reports on phenotypes of heat tolerance, the genetic diversity and polymorphisms in the Heat Shock Protein 70 (HSP70) gene among the Galla goats’ population in Garissa, Isiolo and Tana River Counties. Phenotypic data was collected from 149 Galla goats by the use of a checklist. Blood samples were collected for molecular characterization. Both qualitative and quantitative data for the phenotypic features was carried out. For molecular work, bioinformatics and biostatistics analyses were carried out to infer genetic diversity of the 90 Galla goat samples from all the populations. Analysis of variance for the phenotypic features was determined in response to environmental temperature. Horn and beard presence showed a significant relationship to the environmental temperature. For molecular analysis, a fragment of the D-loop region of the Mitochondrial DNA and that of heat shock protein 70 gene for 96 samples were amplified using convectional Polymerase chain reaction, purified and Sanger sequencing done. A total of 68 mtDNA haplotypes were discovered. Phylogenetic relationship analysis for the haplotypes clustered them into 3 goat haplogroups (haplogroup A, D and G). Analysis of molecular variance showed a huge diversity within populations at 94.39%. For HSP70, 21 haplotypes were discovered. Phylogenetic analysis showed that the haplotypes cluster with sequences from Iraq, China and India. The genetic variation using AMOVA was greatest within populations among groups at 64.66% and showed a high FIS index. This information lays the foundation for informed and controlled genetic breeding for heat tolerant goats and conservation of the Galla goats’ genetic resources. Therefore, the study provides information on the huge diversity