Homoploid hybrid speciation and genome evolution via chromosome sorting.
Genomes of numerous diploid plant and animal species possess traces of interspecific crosses, and many researches consider them as support for homoploid hybrid speciation (HHS), a process by which a new reproductively isolated species arises through hybridization and combination of parts of the parental genomes, but without an increase in ploidy. However, convincing evidence for a creative role of hybridization in the origin of reproductive isolation between hybrid and parental forms is extremely limited. Here, through studying Agrodiaetus butterflies, we provide proof of a previously unknown mode of HHS based on the formation of post-zygotic reproductive isolation via hybridization of chromosomally divergent parental species and subsequent fixation of a novel combination of chromosome fusions/fissions in hybrid descendants. We show that meiotic segregation, operating in the hybrid lineage, resulted in the formation of a new diploid genome, drastically rearranged in terms of chromosome number. We also demonstrate that during the heterozygous stage of the hybrid species formation, recombination was limited between rearranged chromosomes of different parental origin, representing evidence that the reproductive isolation was a direct consequence of hybridization.
Department of Karyosystematics, Zoological Institute of Russian Academy of Sciences, Universitetskaya nab. 1, 199034, St Petersburg, Russia Department of Entomology, St Petersburg State University, Universitetskaya nab. 7/9, 199034, St Petersburg, Russia lukhtanov@mail.ru.
Vladimir A
VA
Lukhtanov
Department of Karyosystematics, Zoological Institute of Russian Academy of Sciences, Universitetskaya nab. 1, 199034, St Petersburg, Russia Department of Entomology, St Petersburg State University, Universitetskaya nab. 7/9, 199034, St Petersburg, Russia.
Nazar A
NA
Shapoval
Department of Karyosystematics, Zoological Institute of Russian Academy of Sciences, Universitetskaya nab. 1, 199034, St Petersburg, Russia.
Boris A
BA
Anokhin
Department of Cytology and Histology, St Petersburg State University, Universitetskaya nab. 7/9, 199034, St Petersburg, Russia.
Alsu F
AF
Saifitdinova
Department of Karyosystematics, Zoological Institute of Russian Academy of Sciences, Universitetskaya nab. 1, 199034, St Petersburg, Russia.
Valentina G
VG
Kuznetsova
D000818:Animals; D005075:Biological Evolution; D002080:Butterflies / Q000235:genetics*; D059006:Chromosomes, Insect / Q000235:genetics*; D003433:Crosses, Genetic; D004171:Diploidy; D049810:Genetic Speciation; D049750:Genome, Insect; D006824:Hybridization, Genetic; D060047:Reproductive Isolation
amplified fragment length polymorphism; chromosome; genomic in situ hybridization; hybrid speciation; meiosis; reproductive isolation