MULTIPLE ORIGINS OF SEX CHROMOSOME FUSIONS CORRELATED WITH CHIASMA LOCALIZATION IN HABRONATTUS JUMPING SPIDERS (ARANEAE: SALTICIDAE)

Entelegyne spiders rarely show fusions yielding neo-Y chromosomes, which M. J. D. White attributed to a constraint in spiders, namely their proximal chiasma localization acting to upset meiotic segregation in males with fusions. Of the 75 taxa of Habronattus and outgroups studied, 47 have X 1 X 2 0...

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Bibliographic Details
Published in:Evolution 2013-08, Vol.67 (8), p.2258-2272
Main Authors: Maddison, Wayne P., Leduc-Robert, Geneviève
Format: Article
Language:English
Subjects:
Animal reproduction
Animals
Autosomes
Biological Evolution
Biological taxonomies
Chiasmata
Chromosome evolution
Chromosomes
Correlation analysis
Evolution
Female
intralocus sexual conflict
Male
Meiosis
neo-Y
Original
Parsimony
phylogenetic correlation
Phylogenetics
segregation constraints
Sex chromosomes
sexual antagonism
Spiders
Spiders - classification
Spiders - cytology
Spiders - genetics
Taxa
X Chromosome
Y Chromosome
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Summary:Entelegyne spiders rarely show fusions yielding neo-Y chromosomes, which M. J. D. White attributed to a constraint in spiders, namely their proximal chiasma localization acting to upset meiotic segregation in males with fusions. Of the 75 taxa of Habronattus and outgroups studied, 47 have X 1 X 2 0 sex chromosomes in males, 10 have X 1 X 2 Y, 15 have X 1 X 2 X 3 Y, 2 have X0, and one has both X 1 X 2 0 and X 1 X 2 X 3 Y. Chromosome numbers and behavior suggest neo-Ys formed by an autosome-X fusion to make X 1 X 2 Y, with a second fusion to an autosome to make X 1 X 2 X 3 Y. Phylogeny shows at least 8–15 gains (or possibly some losses) of neo-Y (i.e., X-autosome fusions), a remarkable number for such a small clade. In contrast to the many X-autosome fusions, at most one autosome–autosome fusion is indicated. Origins of neo-Y are correlated significantly with distal localization of chiasmata, supporting White's hypothesis that evolution of neo-Y systems is facilitated by looser pairing (distal chiasmata) at meiosis. However, an alternative (or contributing) explanation for the correlation is that X-autosome fusions were selected to permit isolation of male-favored alleles to the neo-Y chromosome, aided by distal chiasmata limiting recombination. This intralocus sexual conflict hypothesis could explain both the many X-autosome fusions, and the stunning complexity of male Habronattus courtship displays.
ISSN:0014-3820
1558-5646
DOI:10.1111/evo.12109