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Titre du document / Document title

Environmental versus genetic sex determination: a possible factor in dinosaur extinction?

Auteur(s) / Author(s)

MILLER David (1) ; SUMMERS Jonathan (1) ; SILBER Sherman (2) ;

Affiliation(s) du ou des auteurs / Author(s) Affiliation(s)

(1) University of Leeds, Leeds, ROYAUME-UNI
(2) St. Luke's Hospital, St. Louis, Missouri, ETATS-UNIS

Résumé / Abstract

This study examined the possibility that genetically based sex-determination mechanisms have evolved to ensure a balanced male/female ratio and that this temperature-independent checkpoint might have been unavailable to long-extinct reptiles, notably the dinosaurs. A review of the literature on molecular and phylogenetic relationships between modes of reproduction and sex determination in extant animals was conducted. Mammals, birds, all snakes and most lizards, amphibians, and some gonochoristic fish use specific sex-determining chromosomes or genes (genetic sex determination, GSD). Some reptiles, however, including all crocodilians studied to date, many turtle and tortoise species, and some lizards, use environmental or temperature-dependent sex determination (TSD). We show that various modes of GSD have evolved many times, independently in different orders. Animals using TSD would be at risk of rapid reproductive failure due to a skewed sex ratio favoring males in response to sustained environmental temperature change and favoring the selection of sex-determining genes. The disadvantage to the evolving male sex-determining chromosome. however, is its decay due to nonrecombination and the subsequent loss of spermatogenesis genes. Global temperature change can skew the sex ratio of TSD animals and might have played a significant role in the demise of long-extinct species, notably the dinosaurs, particularly if the temperature change resulted in a preponderance of males. Current global warming also represents a risk for extant TSD species.

Revue / Journal Title

Fertility and sterility    ISSN  0015-0282   CODEN FESTAS 

Source / Source

2004, vol. 81, no4, pp. 954-964 [11 page(s) (article)] (95 ref.)

Langue / Language


Editeur / Publisher

Elsevier, New York, NY, ETATS-UNIS  (1950) (Revue)

Mots-clés anglais / English Keywords



Sex determination




Mots-clés français / French Keywords



Déterminisme sexe




Mots-clés espagnols / Spanish Keywords



Determinismo sexo




Mots-clés d'auteur / Author Keywords

Developmental biology


early development




gene regulation


seasonal reproduction


Localisation / Location

INIST-CNRS, Cote INIST : 4120, 35400011155026.0030

Nº notice refdoc (ud4) : 15624486

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