Indigenous cattle in Africa have adapted to various local environments to acquire superior phenotypes that enhance their survival under harsh conditions. While many studies investigated the adaptation of overall African cattle, genetic characteristics of each breed have been poorly studied. We performed the comparative genome-wide analysis to assess evidence for subspeciation within species at the genetic level in trypanotolerant N’Dama cattle. We analysed genetic variation patterns in N’Dama from the genomes of 101 cattle breeds including 48 samples of five indigenous African cattle breeds and 53 samples of various commercial breeds. Analysis of SNP variances between cattle breeds using wMI, XP-CLR, and XP-EHH detected genes containing N’Dama-specific genetic variants and their potential associations. Functional annotation analysis revealed that these genes are associated with ossification, neurological and immune system. Particularly, the genes involved in bone formation indicate that local adaptation of N’Dama may engage in skeletal growth as well as immune systems. Our results imply that N’Dama might have acquired distinct genotypes associated with growth and regulation of regional diseases including trypanosomiasis. Moreover, this study offers significant insights into identifying genetic signatures for natural and artificial selection of diverse African cattle breeds.
1 September 2019 in International Journal of Systematic and Evolutionary Microbiology
A taxonomic study of a Gram-stain-positive, rod-shaped, non-motile, non-spore-forming, catalase-negative bacterium, isolated from the gut of an insect, Cryptocercus kyebangensis collected from the mountainous area of Seoraksan, Yangyang-gun, Republic of Korea, was conducted. Its 16S rRNA gene sequence showed high similarity values to Weissella ghanensis LMG 24286T (95.9 %), Weissella beninensis 2L24P13T (95.9 %), Weissella fabalis M75T (95.7 %) and Weissella fabaria 257T (95.7 %). The phylogenetic tree indicated that the novel organism formed a cluster with W. ghanensis LMG 24286T, W. beninensis 2L24P13T, W. fabalis M75T and W. fabaria 257T. The G+C content was 41.1 mol% on the basis of the whole-genome sequence. Polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, two unidentified aminophospholipids, one unidentified phospholipid and four unidentified lipids. The major cellular fatty acids were C18 : 1 ω9c, C16 : 0, C14 : 0, summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c) and summed feature 8 (C16 : 1 ω7c and/or C16 : 1 ω6c). The cell-wall peptidoglycan was of A4α type with the interpeptide bridge of Gly-d-Glu. Based on these results, strain 26KH-42T could be classified as a novel species of the genus Weissella , for which the name Weissella cryptocerci sp. nov. is proposed. The type strain is 26KH-42T (=KACC 18423T=NBRC 113066T).
Analyzing the associations between genotypic changes and phenotypic traits on a genome-wide scale can contribute to understanding the functional roles of distinct genetic variations during breed development. We performed a whole-genome analysis of Angus and Jersey cattle breeds using conditional mutual information, which is an information-theoretic method estimating the conditional independency among multiple factor variables. The proposed conditional mutual information-based approach allows breed-discriminative genetic variations to be explicitly identified from tens of millions of SNP (single nucleotide polymorphism) positions on a genome-wide scale while minimizing the usage of prior knowledge. Using this data-driven approach, we identified biologically relevant functional genes, including breed-specific variants for cattle traits such as beef and dairy production. The identified lipid-related genes were shown to be significantly associated with lipid and triglyceride metabolism, fat cell differentiation, and muscle development. In addition, we confirmed that milk-related genes are involved in mammary gland development, lactation, and mastitis-associated processes. Our results provide the distinct properties of Angus and Jersey cattle at a genome-wide level. Moreover, this study offers important insights into discovering unrevealed genetic variants for breed-specific traits and the identification of genetic signatures of diverse cattle breeds with respect to target breed-specific properties.