The study aimed to screen candidate genes associated with litter size in goats and investigate the molecular mechanism by which the RHOU gene regulates goat litter size. The GenoBaits® Goat 40K liquid chip was used to perform SNP genotyping on a hybrid population of 337 Boer goats and Haimen goats under selection, and a genome-wide association study was conducted in combination with the first-parity litter size phenotype. The coding region of the goat RHOU gene was cloned by the PCR method, and its sequence and structural characteristics were analyzed. The large and small follicles and ovarian granulosa cells of goats were isolated, and methods such as RT-qPCR, CCK-8, and ELISA were used to detect gene expression levels, cell proliferation, and estrogen levels. A C/T mutation on chromosome 28 (position 44 302 456, 177 365 bp upstream of RHOU) was significantly associated with first-parity litter size. The cloned RHOU coding region spanned 768 bp, encoding 255 amino acids with high homology to other mammals. The RHOU gene was widely expressed in various tissues of goats, and its expression was extremely significantly higher in ovarian tissue (P<0.01), and the expression level in small follicles was extremely significantly higher than that in large follicles (P<0.01). Overexpression of the RHOU gene significantly reduced cell proliferation ability (P<0.05) and the mRNA expression levels of cell proliferation marker genes PCNA (P<0.05) and MKI67 (P<0.01), and significantly down-regulated the expression level of the CYP19A1 gene and the E2 concentration in the culture medium of goat ovarian granulosa cells (P<0.05). This study identified that the RHOU gene was significantly associated with goat litter size based on the goat 40K liquid chip. The study found that it regulates goat litter performance by negatively regulating the proliferation of goat ovarian granulosa cells, reducing the expression of CYP19A1 in granulosa cells, and inhibiting the synthesis of E2.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |