CHMs are purely androgenetic conceptions (only paternal genetic material is present) and usually diploid (2 paternal chromosome complements without a maternal chromosome complement) (16); most result from fertilization of an ovum devoid of maternal genetic material by a single sperm that duplicates (monospermy; ~85%), (17-19) but a subset is due to fertilization by 2 sperm (
dispermy).
[3] Three different mechanisms can lead to triploidy: (i) a non-disjunction event in meiosis 1 or 2 of spermatogenesis; (ii) non-disjunction in meiosis 1 or 2 of oogenesis; and (iii)
dispermy.
Dispermy is considered to be the most common cause of triploidy.
It has a crucial role in increasing sperm motility and fertilization in bulls with asthenozoospermia due to varicocele and in rabbits with
dispermy caused by cryptorchidism [97].