Genome-wide scans identify known and novel regions associated with prolificacy and reproduction traits in a sub-Saharan African indigenous sheep (Ovis aries)

Abstract

Maximizing the number of offspring born per female is a key functionality trait in commercial-and/or subsistence-oriented livestock enterprises. Although the number of offspring born is closely associated with female fertility and reproductive success, the genetic control of these traits remains poorly understood in sub-Saharan Africa livestock. Using selection signature analysis performed on Ovine HD BeadChip data from the prolific Bonga sheep in Ethiopia, 41 candidate regions under selection were identified. The analysis revealed one strong selection signature on a candidate region on chromosome X spanning BMP15, suggesting this to be the primary candidate prolificacy gene in the breed. The analysis also identified several candidate regions spanning genes not reported before in prolific sheep but underlying fertility and reproduction in other species. The genes associated with female reproduction traits included SPOCK1 (age at first oestrus), GPR173 (mediator of ovarian cyclicity), HB-EGF (signalling early pregnancy success) and SMARCAL1 and HMGN3a (regulate gene expression during embryogenesis). The genes involved in male reproduction were FOXJ1 (sperm function and successful fertilization) and NME5 (spermatogenesis). We also observed genes such as PKD2L2, MAGED1 and KDM3B, which have been associated with diverse fertility traits in both sexes of other species. The results confirm the complexity of the genetic mechanisms underlying reproduction while suggesting that prolificacy in the Bonga sheep, and possibly African indigenous sheep is partly under the control of BMP15 while other genes that enhance male and female fertility are essential for reproductive fitness.

Genome-wide insights on gastrointestinal nematode resistance in autochthonous Tunisian sheep

“…Although we expected the two cohorts to show differences in genetic diversity and structure, this was not the case; they showed similar levels of genetic diversity and inbreeding and the three clustering algorithms provided corroborating evidence of lack of stratification that was consistent with infection status. The lack of genetic differentiation and structure was also reported between prolific and non-prolific cohorts of Bonga sheep from Ethiopia 41 and in the Brazilian Santa Inês breed which shows variability in resistance to GIN infection 19 . The absence of genetic stratification appears to be a characteristic of sheep from the Maghreb as it has also been observed in sheep populations from Algeria 42 and Morocco 43 implicating extensive intermixing and cross-mating.…”

Whole Genome Sequencing Reveals the Effects of Recent Artificial Selection on Litter Size of Bamei Mutton Sheep

“…In addition, in goats, the genes regulating seasonal reproduction and litter size have been specifically selected [ 20 , 21 ]. Moreover, some fecundity-related genes revealed a strong selection signature in sheep from Ethiopia and Europe [ 22 , 23 ].…”

Increased number of large non‐atretic follicles and co‐dominance effects account for high litter sizes in Bonga sheep

“…Recently, our research conducted a selection signature analysis using genome‐wide genotype data from the prolific Bonga sheep in Ethiopia and identified 41 candidate regions associated with fertility and reproduction traits. The analyses confirmed the presence of selection signatures in genomic regions that span or lay adjacent two genes, GDF5 and BMP15 , that are known to be associated with prolificacy (Dolebo et al., 2019). Nevertheless, the physiological mechanisms behind this high and variable performance remain unknown.…”