Genetic Control of Reproductive Traits in Sheep

Reproductive performance in sheep is governed by a complex interplay of genes, regulatory RNAs and hormonal networks that determine ovulation rate, litter size and fertility. Key protein-coding genes such as BMPR1B, BMP15 and GDF9 have been shown to influence follicle development and ovulation, with specific mutations leading to heightened prolificacy in distinct breeds. Beyond these “fecundity genes”, recent work has illuminated the importance of non-coding RNAs—microRNAs and long non-coding RNAs—that fine-tune gene expression within ovarian cells and the hypothalamic-pituitary-gonadal axis. Advances in high-throughput sequencing, single-cell transcriptomics and multiomics integration now allow researchers to map cellular heterogeneity in ovarian tissues, identify novel regulatory networks and discover biomarkers for selection in breeding programmes. Together, these insights underpin strategies for genetic improvement of sheep fertility, with global implications for sustainable meat and wool production, and provide models for understanding mammalian reproductive biology.

Research from Nature Portfolio

Single-cell RNA sequencing of ovine cumulus cells carrying the FecB mutation has revealed distinct differentiation states and cell clusters associated with enhanced ovulation. Analysis showed enrichment of genes in oxidative phosphorylation pathways, suggesting that energy metabolism within cumulus–oocyte complexes is a critical determinant of follicle maturation under prolific genotypes. An earlier genome-wide study of ovarian tissue compared miRNA and long non-coding RNA profiles in high- and low-fecundity sheep. Integrated analyses uncovered regulatory networks in which specific miRNAs and lncRNAs modulate expression of genes involved in follicular growth, extracellular matrix remodelling and steroidogenesis. A complementary co-expression network analysis identified key lncRNAs and hub genes within TGF-β and oxytocin signalling modules, providing candidate regulators that may be harnessed to optimise litter size through targeted breeding.

Genetic Control of Reproductive Traits in Sheep publication trend

The graph below shows the total number of articles in genetic control of reproductive traits in sheep across all publications each year (not limited to Nature Index journals).

Technical terms

FecB mutation: A naturally occurring variant in the BMPR1B gene that increases ovulation rate and litter size in certain sheep breeds.

Granulosa cells: Somatic cells surrounding the oocyte within ovarian follicles that support its growth and secrete hormones.

Cumulus–oocyte complex (COC): The assembly of an oocyte and its surrounding cumulus cells, critical for oocyte maturation and fertilisation.

Oxidative phosphorylation: The mitochondrial process generating ATP, essential for energy-dependent stages of follicle and oocyte development.

MicroRNA (miRNA): Short non-coding RNA molecules that bind to messenger RNAs to repress translation or induce degradation.

Long non-coding RNA (lncRNA): RNA transcripts longer than 200 nucleotides that regulate gene expression through diverse mechanisms.

Single-cell RNA sequencing (scRNA-seq): A method to profile gene expression at the individual cell level, revealing cellular heterogeneity.

References

1. Multiomics Analyses Provide New Insight into Genetic Variation of Reproductive Adaptability in Tibetan Sheep. Molecular Biology and Evolution (2024).
2. Integration analysis of pituitary proteome and transcriptome reveals fertility–related biomarkers in FecB mutant Small Tail Han sheep. Frontiers in Endocrinology (2024).
3. Single-cell RNA-seq reveals the effects of the FecB mutation on the transcriptome profile in ovine cumulus cells. Scientific Reports (2024).
4. Ovarian transcriptomic study reveals the differential regulation of miRNAs and lncRNAs related to fecundity in different sheep. Scientific Reports (2016).
5. Co-expression analysis and identification of fecundity-related long non-coding RNAs in sheep ovaries. Scientific Reports (2016).