Mating of a babirusa (Babyrousa babyrussa) boar and a domestic sow (Sus scrofa) resulted in the birth of 5 live domestic pig-babirusa hybrid piglets. Chromosome analysis of one of the surviving males confirmed that they were domestic pig-babirusa hybrids by revealing the presence of a complete haploid set of 19 porcine chromosomes as well as a complete haploid set of 19 babirusa chromosomes in the karyotype. None of the surviving piglets, two males and one female, had shown signs of sexual maturity at age 27 months. Histological examination of gonadal biopsies from the 2 males revealed that both were azoospermatic. Immunostaining revealed SCP3-positive axial elements in the nuclei of primary spermatocytes, indicating that they were progressing through leptotene and zygotene of meiotic prophase. However, the presence of multiple short stretches of axial elements in pachytene nuclei indicated that this phase was blocked, probably due to aberrant chromosome pairing. Histological examination of the ovaries revealed follicular structures, but oocytes within them were generally degenerated. We conclude that both male and female pig-babirusa hybrids were infertile, most likely due to germ cell death resulting from abnormalities of chromosome pairing during meiotic prophase.

Bosma AA, de Haan NA, Mellink CH, Yerle M, Zijlstra C: Chromosome homology between the domestic pig and the babirusa (family Suidae) elucidated with the use of porcine painting probes. Cytogenet Cell Genet 75:32–35 (1996).
Committee for the Standardized Karyotype of the Domestic Pig. Standard karyotype of the domestic pig. Hereditas 109:151–157 (1988).
Haldane JBS: Sex ratio and unisexual sterility in hybrid animals. J Genet 12:101–109 (1922).
Li XC, Barringer BC, Barbash DA: The pachytene checkpoint and its relationship to evolutionary patterns of polyploidization and hybrid sterility. Heredity 102:24–30 (2009)
Pfeifer C, Thomsen PD, Scherthan H: Centromere and telomere redistribution precedes homologue pairing and terminal synapsis initiation during prophase I of cattle spermatogenesis. Cytogenet Cell Genet 93:304–314 (2001).
Pfeifer C, Scherthan H, Thomsen PD: Sex-specific telomere redistribution and synapsis initiation in cattle oogenesis. Dev Biol 255:206–215 (2003).
Scherthan H, Weich S, Schwegler H, Heyting C, Harle M, Cremer T: Centromere and telomere movements during early meiotic prophase of mouse and man are associated with the onset of chromosome pairing. J Cell Biol 134:1109–1125 (1996).
Thomsen PD, Hoeyheim B, Christensen K: Recent fusion events during evolution of pig chromosomes 3 and 6 identified by comparison with the babirusa karyotype. Cytogenet Cell Genet 73:203–208 (1996).
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