Sex-Influenced Genes for Horn in Sheep
The sheep of the Dorset -breed possess horns in both of the sexes, while, both sexes of suffolk breed are hornless. The genes for horned condition (HH) are dominant over recessive genes (hh) for hornless condition. When a pure-line horned sheep is crossed with a pure line hornless sheep, then the heterozygous genotype, Hh, is found to be sex-influenced, with the males having horns and the females having no horns. The inheritance of sex-influenced genes for horns in sheep can be represented diagrammatically as follows:
| Parent : | Dorset sheep HH |
X | Suffolk sheep hh |
| F1: | Hh | ||
| (Horned male and hornless female) | |||
| F2: | Male - HH, Hh, Hh Horned |
hh Hornless |
|
| Female - HH Horned |
Hh, Hh. hh Hornless |
||