Why do fraternal twins skip a generation?
Fraternal twins ‘sometimes’ skip a generation because it is a female-linked trait. The fraternal twinning gene causes 2 eggs to be produced at ovulation instead of 1, resulting in fraternal twins. A male or a female could carry the genetics to have fraternal twins, but only a female could express that trait. Therefore it could appear to skip generation if the trait is carried by male child. For example a woman might carry the fraternal twinning gene and she may have a set of fraternal twins, lets say two boys. These boys may carry the gene for fraternal twins, but because he doesn’t produce eggs, he can not express this gene. So when has children, he will not be likely to have fraternal twins, even though he is carrying the gene. However, he will pass on the fraternal twinning gene he is carrying to his daughters, who will be likely to have fraternal twins when they have children. So basically the reason fraternal twins skip a generation is that the trait is hidden in males. Example: G
