Categories: Reproductive system phene

Links to possible relevant human trait(s) and/or gene(s) in OMIM: 602931 (gene)

Mendelian trait/disorder: unknown

Disease-related: no

Species-specific name: Trio

Species-specific description: Constantino et al. (2023): "The bovine high fecundity allele, Trio, causes overexpression in granulosa cells of SMAD6, an inhibitor of BMP15-activated SMAD signalling. Furthermore, the Trio allele results in antral follicles that develop slower, acquire ovulatory capacity at smaller sizes, and have 3-fold greater ovulation rate compared to half-sib non-carriers."

History: Morris et al. (2010) reported a mixed-breed cow of uncertain heritage that was named "Treble" on account of her three sets of triplets. Five of the daughters of one her her triplet sons (named "Trio") produced 6 sets of triplets. As concluded by the authors: "Treble is a cow of remarkable reproductive performance, with three sets of triplets. The fact that some of her grand-daughters also produced triplets strongly suggests that some of her ability is inherited."

Mapping: A genome-wide linkage analysis of 131 daughters of the hypothesised carrier bull Trio, each genotyped with 3K SNPs, enabled Kirkpatrick and Morris (2014) to map high ovulation rate (over 4 cycles) to a region of chromosome BTA10. Then, as reported by these same authors, "Haplotype analysis of the sire, recombinant daughters and a subset of non-recombinant daughters using 50k SNP genotype data narrowed the positional candidate region to an area of approximately 1.5 Mb". Kirkpatrick and Morris (2015) narrowed this slightly to "a 1.2 Mb region between 13.6 and 14.8 Mb on chromosome 10".

Genetic testing: Kirkpatrick and Morris (2015) identified "three polymorphisms were identified that can be used as a haplotype to track inheritance of the high ovulation rate allele in descendants of the carrier sire."