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GENETICS OF STERILITY IN HYBRIDS BETWEEN TWO SUBSPECIES OF DROSOPHILA
Author(s) -
Orr H. Allen
Publication year - 1989
Publication title -
evolution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.84
H-Index - 199
eISSN - 1558-5646
pISSN - 0014-3820
DOI - 10.1111/j.1558-5646.1989.tb04216.x
Subject(s) - biology , drosophila pseudoobscura , sterility , reproductive isolation , hybrid , genetics , subspecies , evolutionary biology , chromosome , drosophila (subgenus) , incipient speciation , genetic algorithm , zoology , genetic variation , population , gene , botany , gene flow , demography , sociology
Hybrids between D. pseudoobscura bogotana and D. pseudoobscura pseudoobscura are fertile except for males produced in one of the two reciprocal crosses. As there is no premating isolation between these subspecies, nonreciprocal male sterility represents the first step in speciation. Genetic analysis reveals two causes of hybrid F 1 sterility: a maternal effect and incompatibilities between chromosomes within males. The maternal effect appears to play the greatest role in hybrid sterility. The X chromosome has the largest effect on fertility of any chromosome, a ubiquitous result in analyses of hybrid sterility and inviability in Drosophila. This effect is entirely attributable to a region comprising less than 30% of the X chromosome. These results are compared to those from a similar study of D. pseudoobscura‐D. persimilis hybrids, an older and more reproductively isolated species pair in the same lineage. Such comparisons may allow one to identify the genetic changes characterizing the early versus late stages of speciation.