Search Results (4)

This study investigates the genetic architecture of the Kazakh Whiteheaded (KWH) cattle, applying population genetics approaches to resequenced genomes. F_ST analysis of 66 cattle breeds identified breeds for admixture analysis. At K = 19, the composite KWH breed showed contributions from Hereford, Altai, and Kalmyk cattle. Principal component analysis and ancestry inference confirmed these patterns, with KWH genomes comprising 45% Hereford, 30% Altai, and 25% Kalmyk ancestries. Haplotype analysis revealed 73 regions under putative selection in KWH, some shared with Hereford (e.g., with the gene DCUN1D4) and some KWH-specific (e.g., with the gene SCMH1). F_ST analysis identified 105 putative intervals under selection, with key genes (KITLG, SLC9C1, and SCMH1) involved in coat colour and physiological adaptations. Functional enrichment using The Database for Annotation, Visualization, and Integrated Discovery (DAVID) in selected regions highlighted clusters associated with developmental processes, ubiquitination, and fatty acid metabolism. Point F_ST identified 42 missense variants in genes enriched in functions related to economically important traits. Local ancestry inference revealed genomic intervals with predominantly non-Hereford ancestry, including high Altai (e.g., SCAPER) and Kalmyk (e.g., SRD5A2) contributions, while Hereford-dominated regions included genes ENO1 and RERE. This work elucidates the genomic contributions and adaptive signatures of selection shaping the KWH breed, providing candidate genetic variants for breeding program improvement and enhanced genome predictions. Full article

In vitro fertilization (IVF) technologies have great potential in the preservation of endangered species. In the current study, an IVF experiment was carried out to evaluate whether reproductive technologies are suitable for Kazakh Whiteheaded cattle, aimed at preserving this breed whose population has reduced drastically over the last thirty years. The reproduction characteristics of Kazakh Whiteheaded cows were compared to Aberdeen Angus cows. Transvaginal ultrasound-guided ovum pick up sessions were carried out followed by in vitro embryo production and embryo transfer and pregnancy diagnosis. The total and viable oocytes per OPU procedure were 12.8 ± 1.18 and 8.7 ± 0.85 for the Aberdeen Angus breed, and 8.8 ± 1.04 and 6.2 ± 0.83 for the Kazakh Whiteheaded breed. Similarly, the mean number of cleaved oocytes and morula/blastocyst stage embryos produced by OPU/IVF were 4.8 ± 0.49 and 1.4 ± 0.15 for the Aberdeen Angus breed, and 2.4 ± 0.46 and 0.18 ± 0.05 for the Kazakh Whiteheaded breed (p ≤ 0.02). From fifty Kazakh Whiteheaded donor animals, 2585 oocytes were aspirated following six ovum pick up sessions. One thousand eight hundred and seventy-six (72.5%) oocytes were chosen for maturation and were further fertilized. The number of embryos cleaved was 720 (38.3% out of oocytes fertilized) on day four post-fertilization. Of these cleaved embryos, 56 (7.5%) developed into the late morula/blastocyst stage on day seven post-fertilization, averaging 1.12 embryos per donor animal. Pregnancy was detected in 12 recipients; 4 healthy calves have been born to date. The outcomes of our study have demonstrated that reproductive technologies can be applicable in preserving the endangered Kazakh Whiteheaded cattle. The findings in this report will enhance knowledge of the reproductive characteristics of endangered domestic animals and help develop sophisticated reproductive protocols for animals with unique reproductive mechanisms. Full article

Runs of homozygosity (ROH) are contiguous stretches of homozygous genotypes that are passed from parents to their offspring. ROHs are suitable for determining population history, inbreeding rates, and the genetic relationships between individuals in the populations, as well as to detect candidate genes responsible for economic traits in farm animals. In this study, we observed that the Kazakh white-headed (KWh) cattle breed (ROH n = 55,976) had a higher number of ROH compared to the Auliekol (AK) breed (ROH n = 13,137). When calculating the mean length of ROH, there were considerable differences between Kazakh white-headed (211.59 ± 92.98 Mb) and Auliekol (99.62 ± 46.48 Mb) populations. The maximum length of ROH was higher in Auliekol cattle (510.25 Mb) than in Kazakh white-headed cattle (498.91 Mb). The average inbreeding coefficient rate was equal to 0.084 ± 0.037 in Kazakh white-headed cattle and 0.039 ± 0.018 in Auliekol cattle. The high frequency of genomic regions showed that the strongest patterns were observed on chromosomes 2, 6, and 26 for KWh and 1, 5, and 14 for AK. The estimation of ROH numbers per animal showed that the number of ROH decreased with increasing ROH length in both populations. The genomic inbreeding coefficient of both cattle breeds was calculated based on the ROH, and ancient inbreeding was observed. The harbored genes within ROH islands were associated with meat growth and milk production. Full article

The comparative molecular genetic study of museum and modern representatives of cattle breeds can help to elucidate the origin and maintenance of historical genetic components in modern populations. We generated the consensus genotypes for 11 microsatellite loci for 24 museum samples of Kalmyk, Kyrgyz, and Kazakh cattle, dated from the first quarter of the 20th century, and compared them with those of modern Kalmyk, Kyrgyz, and Kazakh white-headed breeds. The level of genetic diversity of the modern Kalmyk and Kyrgyz cattle (uHe = 0.771–0.778) was similar to those observed in the museum samples (uHe = 0.772–0.776), while a visible decrease in genetic variability in the modern Kazakh white-headed breed compared to museum Kazakh cattle was detected (uHe = 0.726 and 0.767, respectively). The PCA plot, F_ST- and Jost’s D-based networks, and STRUCTURE clustering provided strong evidence of the maintenance of the historical genetic background in modern populations of Kalmyk and Kyrgyz cattle. In spite of the allele pool of Kazakh white-headed cattle having undergone great changes compared to the museum Kazakh cattle, several animals still carry the visible aspect of the historical genetic components. Our results can be used for the selection of individuals for the creation of gene banks and may significantly improve the efficiency of conservation programs aimed at preserving genetic diversity in the national genetic resources of cattle. Full article