Evidence for independent domestication of sheep mtDNA lineage A in India and introduction of lineage B through Arabian sea route

Ancient mitogenomes from Pre-Pottery Neolithic Central Anatolia and the effects of a Late Neolithic bottleneck in sheep (Ovis aries)

Occupied between ~10,300 and 9300 years ago, the Pre-Pottery Neolithic site of Aşıklı Höyük in Central Anatolia went through early phases of sheep domestication. Analysis of 629 mitochondrial genomes from this and numerous sites in Anatolia, southwest Asia, Europe, and Africa produced a phylogenetic tree with excessive coalescences (nodes) around the Neolithic, a potential signature of a domestication bottleneck. This is consistent with archeological evidence of sheep management at Aşıklı Höyük which transitioned from residential stabling to open pasturing over a millennium of site occupation. However, unexpectedly, we detected high genetic diversity throughout Aşıklı Höyük's occupation rather than a bottleneck. Instead, we detected a tenfold demographic bottleneck later in the Neolithic, which caused the fixation of mitochondrial haplogroup B in southwestern Anatolia. The mitochondrial genetic makeup that emerged was carried from the core region of early Neolithic sheep management into Europe and dominates the matrilineal diversity of both its ancient and the billion-strong modern sheep populations.

Phylogenetic Analysis of Russian Native Sheep Breeds Based on mtDNA Sequences

Eurasia is represented by all climatic zones and various environments. A unique breed variety of farm animals has been developed in Russia, whose territory covers a large area of the continent. A total of 69 local breeds and types of dairy, wool, and meat sheep (Ovis aries) are maintained here. However, the genetic diversity and maternal origin of these local breeds have not been comprehensively investigated. In this study, we describe the diversity and phylogeny of Russian sheep breeds inhabiting different geographical regions based on the analysis of complete sequences of mitochondrial genomes (mtDNA). Complete mtDNA sequences of the studied sheep were obtained using next-generation sequencing technology (NGS). All investigated geographical groups of sheep were characterized by high haplotype (Hd = 0.9992) and nucleotide diversity (π = 0.00378). Analysis of the AMOVA results showed that genetic diversity was majorly determined by within-population differences (77.87%). We identified 128 haplotypes in all studied sheep. Haplotypes belonged to the following haplogroups: B (64.8%), A (28.9%), C (5.5%), and D (0.8%). Haplogroup B was predominant in the western part of Russia. A high level of mtDNA polymorphism in the studied groups of local sheep indicates the presence of a significant reserve of unique genotypes in Russia, which is to be explored.

Genetic diversity and relationship among Indonesian local sheep breeds on Java Island based on mitochondrial cytochrome b gene sequences

BACKGROUND

The cytochrome b (Cyt b) gene is one of the most studied mitochondrial DNA (mtDNA) genes to determine sheep's genetic profile. This study aimed to determine the genetic diversity and relationships of several Indonesian local sheep populations on Java Island, Indonesia, based on the mtDNA Cyt b gene sequences. Blood samples were collected from forty-one individual sheep in seven populations of Indonesia local sheep breeds on Java Island (Priangan = 6, Garut = 6, Batur = 7, Wonosobo = 5, Javanese Thin-Tailed/JTT = 7, Javanese Fat-Tailed/JFT = 5, and Sapudi = 5). DNA extraction was performed on blood samples, and the mtDNA Cyt b gene was amplified using specific primers (Alek-CBF: 5'-CAACCCCACCACTTACAA-3' and Alek-CBR: 5'-CCTTGAGTCTTAGGGAGGTT-3'). The polymerase chain reaction (PCR) products were then sequenced, and data were analyzed using the MEGA version 7.0, DNA SP version 6.0, and NTSYS-pc version 2.11 software.

RESULTS

A total of 1140 bp complete mtDNA Cyt b gene sequences in this study obtained 1134 monomorphic sites (I), six polymorphic sites (V), one segregation site (S), and five parsimony informative sites (P) with a nucleotide diversity (Pi), the average number of nucleotide differences (K), and sequence conservation (SC) were 0.00119, 1.35610, and 0.9947, respectively. There were six haplotypes consisting of two unique haplotypes and four shared haplotypes with a haplotype diversity (Hd) of 0.5415. The genetic distance within and between populations ranged from 0.0000 to 0.0016 and 0.0000 to 0.0020, respectively. Wonosobo, JFT, and Sapudi sheep have the closest relationship, and then these three breeds were close to JTT sheep, followed by Batur, Priangan, and Garut sheep. Two haplogroups have been found based on the Ovine haplogroup clustering. All Wonosobo, JTT, JFT, Sapudi sheep, and most Batur sheep were clustered into haplogroup B. In contrast, Garut sheep were mostly clustered into haplogroup A, while Priangan sheep were clustered into both haplogroups with the same percentage.

CONCLUSION

Seven Indonesian local sheep breeds on Java Island have a close relationship clustered into two haplogroups, namely haplogroups A and B. Most Indonesian local sheep breeds on Java Island in this study were clustered into haplogroup B, except for Garut and Priangan sheep.