A cryptic heterogametic transition revealed by sex-linked DNA markers in Palearctic green toads.

Détails

ID Serval
serval:BIB_BBCA86C43C58
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
A cryptic heterogametic transition revealed by sex-linked DNA markers in Palearctic green toads.
Périodique
Journal of Evolutionary Biology
Auteur(s)
Stöck M., Croll D., Dumas Z., Biollay S., Wang J., Perrin N.
ISSN
1420-9101 (Electronic)
ISSN-L
1010-061X
Statut éditorial
Publié
Date de publication
2011
Peer-reviewed
Oui
Volume
24
Numéro
5
Pages
1064-1070
Langue
anglais
Résumé
In sharp contrast to birds and mammals, most cold-blooded vertebrates have homomorphic (morphologically undifferentiated) sex chromosomes. This might result either from recurrent X-Y recombination (occurring e.g. during occasional events of sex reversal) or from frequent turnovers (during which sex-determining genes are overthrown by new autosomal mutations). Evidence for turnovers is indeed mounting in fish, but very few have so far been documented in amphibians, possibly because of practical difficulties in identifying sex chromosomes. Female heterogamety (ZW) has long been established in Bufo bufo, based on sex reversal and crossing experiments. Here, we investigate a sex-linked marker identified from a laboratory cross between Palearctic green toads (Bufo viridis subgroup). The F(1) offspring produced by a female Bufo balearicus and a male Bufo siculus were phenotypically sexed, displaying an even sex ratio. A sex-specific marker detected in highly reproducible AFLP genotypes was cloned. Sequencing revealed a noncoding, microsatellite-containing fragment. Reamplification and genotyping of families of this and a reciprocal cross showed B. siculus to be male heterogametic (XY) and suggested the same system for B. balearicus. Our results thus reveal a cryptic heterogametic transition within bufonid frogs and help explain patterns of hybrid fitness within the B. viridis subgroup. Turnovers of genetic sex-determination systems may be more frequent in amphibians than previously thought and thus contribute to the prevalence of homomorphic sex chromosomes in this group.
Mots-clé
amphibians, Bufo viridis subgroup, male heterogamety, sex chromosomes, sex-linked marker, Animals, Bufonidae/genetics, Female, Genotype, Male, Microsatellite Repeats, Sex Chromosomes, Sex Determination Processes
Pubmed
Web of science
Open Access
Oui
Création de la notice
13/01/2011 23:41
Dernière modification de la notice
20/08/2019 16:29
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