Sex-determining mechanisms in vertebrates

doi:10.1017/CBO9780511542053.008

Chapter 7 - Sex-determining mechanisms in vertebrates

Published online by Cambridge University Press: 06 August 2009

Sarah B.M. Kraak and

Ido Pen

Edited by

Ian C. W. Hardy

Show author details

Sarah B.M. Kraak: Affiliation:
Netherlands Institute for Fisheries, Research, The Netherlands
Ido Pen: Affiliation:
Zoological Laboratory, University of Groningen, The Netherlands
Ian C. W. Hardy: Affiliation:
University of Nottingham

Book contents

Get access

Summary

Vertebrates have various sex-determining mechanisms. These have been broadly classified as either genotypic sex determination (GSD) or environmental sex determination (ESD). This terminology, however, may obscure the facts that mixtures between genotypic and environmental sex determination exist, and that genotypic and environmental sex determination may themselves be the extremes of a continuum. Sex ratio evolution plays an important role in the evolution of sex-determining mechanisms.

Introduction

This chapter starts with the proximate aspects of sex-determining mechanisms (section 7.3). We introduce the traditional classification of sex-determining mechanisms that exist in vertebrates (section 7.3.1) and the distribution of mechanisms among extant vertebrate taxa (section 7.3.2). At phylogenetically shallow levels, different mechanisms are present. We describe how the existence of either male or female heterogamety, or ESD is usually established for individual species or taxa (section 7.3.3). Cases of mixed sex determination, i.e. combinations of GSD and ESD, are also observed (section 7.3.4) and we caution that this phenomenon has implications for sex identification by molecular markers (section 7.3.5). We stress that phenotypic sex generally has environmental and genetic components and discuss a model that attempts to unify sex determination by stating that sex determination in all vertebrates is mediated by differential growth of the embryo (section 7.3.6).

In the second part of the chapter we discuss the evolution of sex-determining mechanisms. Evolution from one system to another can be quite rapid (section 7.4). We stress that sex ratio selection plays an important role in the evolution of sex-determining mechanisms (section 7.4.1).

Type: Chapter
Information: Sex Ratios
Concepts and Research Methods
, pp. 158 - 177

DOI: https://doi.org/10.1017/CBO9780511542053.008 [Opens in a new window]

Publisher: Cambridge University Press

Print publication year: 2002

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

Book purchase

Temporarily unavailable

References

Beamish, F W (1993) Environmental sex determination in southern brook lamprey, Ichthyomyzon gagei. Canadian Journal of Fisheries and Aquatic Sciences, 50, 1299–1307CrossRef Google Scholar

Beatty RA (1964) Chromosome deviations and sex in vertebrates. In: C N Armstrong & A J Marshall (eds) Intersexuality in Vertebrates Including Man, pp 17–143. London: Academic Press

Bennett, C P, Docherty, Z, Robb, S A, Ramani, P, Hawkins, J R & Grant, D (1993) Deletion 9p and sex reversal. Journal of Medical Genetics, 30, 518–520CrossRef Google Scholar PubMed

Bertollo, L A C & Cavallaro, Z I (1992) A highly differentiated ZZ/ZW sex-chromosome system in a Characidae fish, Triportheus guenteri. Cytogenetics and Cell Genetics, 60, 60–63CrossRef Google Scholar

Blázquez, M, Carrillo, M, Zanuy, S & Piferrer, F (1999) Sex ratios in offspring of sex-reversed sea bass and the relationship between growth and phenotypic sex differentiation. Journal of Fish Biology, 55, 916–930CrossRef Google Scholar

Bull, J J (1980) Sex determination in reptiles. The Quarterly Review of Biology, 55, 3–21CrossRef Google Scholar

Bull J J (1983) Evolution of Sex Determining Mechanisms. Menlo Park: Benjamin/Cummings

Bull, J J, Vogt, R C & Bulmer, M G (1982) Heritability of sex ratio in turtles with environmental sex determination. Evolution, 36, 333–341CrossRef Google Scholar PubMed

Bull, J J, Hillis, D M H & O'Steen, S (1988) Mammalian ZFY sequences exist in reptiles regardless of sex-determining mechanisms. Science, 242, 567–569CrossRef Google Scholar

Burgoyne, P S, Thornhill, A R, Kalmus, Boudrean S, Darling, S M, Bishop, C E & Evans, E P (1995) The genetic basis of XX-XY differences present before gonadal sex differentiation in the mouse. Philosophical Transactions of the Royal Society of London, series B, 350, 253–261CrossRef Google Scholar PubMed

Caputo, V, Odierna, G & Aprea, G (1994) A chromosomal study of Eumeces and Scincus, primitive members of the Scincidae (Reptilia, Squamata). Bollettino di Zoologia, 61, 155–162CrossRef Google Scholar

Carr, J L & Bickham, J W (1981) Sex chromosomes of the Asian black pond turtle Siebenrockiella crassicollis (Testudines: Emydidae). Cytogenetics and Cell Genetics, 31, 178–183CrossRef Google Scholar

Cattanach, B M, Rasberry, C & Beechey, C V (1995) XY sex reversal associated with autosomal deletions. Mouse Genome, 93, 426Google Scholar

Charlesworth, B (1996) The evolution of chromosomal sex determination and dosage compensation. Current Biology, 6, 140–162CrossRef Google Scholar PubMed

Charlesworth, B & Charlesworth, D (2000) The degeneration of Y chromosomes. Philosophical Transactions of the Royal Society of London, series B, 355, 1563–1572CrossRef Google Scholar PubMed

Charnov E L (1982) The Theory of Sex Allocation. Princeton, NJ: Princeton University Press

Charnov, E L & Bull, J J (1977) When is sex environmentally determined?Nature, 266, 828–830CrossRef Google Scholar PubMed

Chourrout, D (1986) Revue sur le déterminisme genétique du sexe des poissons téléostéens. Bulletin de la Socitété Zoologique de France, 113, 123–144Google Scholar

Ciofi, C & Swingland, I R (1997) Environmental sex determination in reptiles. Applied Animal Behaviour Science, 51, 251–265CrossRef Google Scholar

Cole, C J (1971) Karyotypes of the five monotypic species groups of lizards in the genus Sceloporus. American Museum Novitates, 2450, 1–17Google Scholar

Conover, D O & Heins, S W (1987) Adaptive variation in environmental and genetic sex determination in a fish. Nature, 326, 496–498CrossRef Google Scholar PubMed

Coriat, A-M, Muller, U, Harry, J L, Uwanogho, D & Sharpe, P T (1993) PCR amplification of SRY-related gene sequences reveals evolutionary conservation of the SRY-related motif. PCR Methods and Applications, 2, 218–222CrossRef Google Scholar PubMed

Coriat, A-M, Valleley, E, Ferguson, M W J & Sharpe, P T (1994) Chromosomal and temperature-dependent sex determination: the search for a conserved mechanism. The Journal of Experimental Zoology, 270, 112–116CrossRef Google Scholar PubMed

Coughlan, T, Schartl, M, Hornung, U, Hope, I & Stewart, A (1999) PCR-based sex test for Xiphophorus maculatus. Journal of Fish Biology, 54, 218–222CrossRef Google Scholar

Craig, J K, Foote, C J & Wood, C C (1996) Evidence for temperature-dependent sex determination in sockeye salmon (Oncorhynchus nerka). Canadian Journal of Fisheries and Aquatic Sciences, 53, 141–147CrossRef Google Scholar

Cree, A, Thompson, M B & Daugherty, C H (1995) Tuatara sex determinationNature, 375, 543CrossRef Google Scholar

Daan, S, Dijkstra, C & Weissing, F J (1996) An evolutionary explanation for seasonal sex ratio trends in avian sex ratios. Behavioral Ecology, 7, 426–430CrossRef Google Scholar

Deeming, D C & Ferguson, M W J (1988) Environmental regulation of sex determination in reptiles. Philosophical Transactions of the Royal Society of London, series B, 322, 19–39CrossRef Google Scholar PubMed

Deeming DC & Ferguson MWJ (1991) Physiological effects of incubation temperature on embryonic development in reptiles and birds. In: D C Deeming & M W J Ferguson (eds) Egg Incubation: Its Effects on Embryonic Development in Birds and Reptiles, pp 147–171. Cambridge: Cambridge University Press

Demas, S, Duronslet, M, Wachtel, S, Caillouet, C & Nakamura, D (1990) Sex-specific DNA in reptiles with temperature sex determination. The Journal of Experimental Zoology, 253, 319–324CrossRef Google Scholar PubMed

Devlin, R H, McNeil, B K, Solar, II & Donaldson, E M (1994) A rapid PCR-based test for Y-chromosomal DNA allows simple production of all-female strains of chinook salmon. Aquaculture, 128, 211–220CrossRef Google Scholar

Docker, M F & Beamish, F W H (1994) Age, growth, and sex ratio among populations of least brook lamprey, Lampetra aepyptera, larvae – an argument for environmental sex determination. Environmental Biology of Fishes, 41, 191–205CrossRef Google Scholar

Dorazi, R, Chesnel, A & Dournon, C (1995) Opposite sex determination of gonads in two Pleurodeles species may be due to a temperature-dependent inactivation of sex chromosomes. Journal of Heredity, 86, 28–31CrossRef Google Scholar

Duellman W E & Trueb L (1986) Biology of Amphibians. New York: McGraw-Hill

Ellegren, H & Sheldon, B C (1997) New tools for sex identification and the study of sex allocation in birds. Trends in Ecology and Evolution, 12, 255–259CrossRef Google Scholar

Engel, W & Schmid, M (1981) H-Y antigen as a tool for the determination of the heterogametic sex in Amphibia. Cytogenetics and Cell Genetics, 30, 130–136CrossRef Google Scholar PubMed

Engel, W, Klemme, B & Schmid, M (1981) H-Y antigen and sex determination in turtles. Differentiation, 20, 152–156CrossRef Google Scholar

Erickson, R P (1997) Does sex determination start at conception?BioEssays, 19, 1027–1032CrossRef Google Scholar PubMed

Ewert MA, Etchberger CR & Nelson CE (1990) An apparent co-occurrence of genetic and environmental sex determination in a turtle. American Zoologist, 30, 56A

Ewert, M A, Jackson, D R & Nelson, C E (1994) Patterns of temperature-dependent sex determination in turtles. The Journal of Experimental Zoology, 270, 3–15CrossRef Google Scholar

Ferguson MWJ (1994a) Temperature dependent sex determination and growth in reptiles and manipulation of poultry sex by incubation temperature. In: Proceedings of the 9th European Poultry Conference in Glasgow, pp 380–382

Ferguson MWJ (1994b) Method of hatching avian eggs. Patent WO 94/13132

Ford, L S & Cannatella, D C (1993) The major clades of frogs. Herpetological Monographs 7, 94–117CrossRef Google Scholar

Francis, R C (1992) Sexual lability in teleosts: developmental factors. The Quarterly Review of Biology, 67, 1–18CrossRef Google Scholar

Francis, R C & Barlow, G W (1993) Social control of primary sex differentiation in the Midas cichlid. Proceedings of the National Academy of Sciences, USA 90, 10673–10675CrossRef Google Scholar PubMed

Frank, S A & Swingland, I R (1988) Sex ratio under conditional sex expression. Journal of Theoretical Biology, 135, 415–418CrossRef Google Scholar PubMed

Fredga K (1994) Bizarre mammalian sex-determining mechanisms. In: R V Short & E Balaban (eds) The Difference Between the Sexes, pp 419–431. Cambridge: Cambridge University Press

Fredga, K, Gropp, A, Winking, H & Frank, F (1976) Fertile XX- and XY- females in the wood lemming Myopus schisticolor. Nature 261, 225–227CrossRef Google Scholar PubMed

Gaffney ES & Meylan PA (1988) A phylogeny of turtles. In: M J Benton (ed) The Phylogeny and Classification of the Tetrapods, volume 1, Amphibians, Reptiles, Birds, pp 157–219. Oxford: Clarendon Press

Ganesh, S, Mohanty, J & Raman, R (1997) Male-biased distribution of the human Y chromosomal genes SRY and ZFY in the lizard Calotes versicolor, which lacks sex chromosomes and temperature-dependent sex determination. Chromosome Research, 5, 413–419CrossRef Google Scholar

Gauthier J, Estes R & de Queiroz K (1988) A phylogenetic analysis of Lepidosauromorpha. In: R Estes & G Pregill (eds) Phylogenetic Relationships of the Lizard Families, pp 15–98. Stanford: Stanford University Press

Girondot, M, Zaborski, P, Servan, J & Pieau, C (1994) Genetic contribution to sex determination in turtles with environmental sex determination. Genetical Research, Cambridge, 63, 117–127CrossRef Google Scholar

Goodfellow, P N & Lovell-Badge, R (1993) The SRY and sex determination in mammals. Annual Review of Genetics, 27, 71–92CrossRef Google Scholar PubMed

Gorman GC (1973) The chromosomes of the reptilia, a cytotaxonomic interpretation. In: A B Chiarelli & E Capanna (eds) Cytotaxonomy and Vertebrate Evolution, pp 349–424. London: Academic Press

Goto, R, Kayaba, T, Adachi, S & Yamauchi, K (2000) Effects of temperature on sex determination in marble sole Limanda yokohamae. Fisheries Science, 66, 400–402CrossRef Google Scholar

Griffiths, R (1991) The isolation of conserved DNA sequences related to the human sex-determining region of Y gene from the lesser black-backed gull (Larus fuscus). Proceedings of the Royal Society of London, series B, 244, 123–128CrossRef Google Scholar

Griffiths, R, Daan, S & Dijkstra, C (1996) Sex identification in birds using two CHD genes. Proceedings of the Royal Society of London, series B, 263, 1251–1256CrossRef Google Scholar PubMed

Gubbay, J, Collignon, J, Koopman, P, Capel, B, Economou, A, Münsterberg, A, Vivian, N, Goodfellow, P & Lovell-Badge, R (1990) A gene mapping to the sex-determining region of the mouse Y chromosome is a member of a novel family of embryonically expressed genes. Nature, 346, 245–250CrossRef Google Scholar PubMed

Haig, D (1991) Developmental asynchrony and environmental sex determination in alligators. Journal of Theoretical Biology, 150, 373–383CrossRef Google Scholar

Hayes, T B (1998) Sex determination and primary sex differentiation in amphibians: genetic and developmental mechanisms. Journal of Experimental Zoology, 281, 373–3993.0.CO;2-L>CrossRef Google Scholar PubMed

Head, G, May, R M & Pendleton, L (1987) Environmental determination of sex in the reptiles. Nature, 329, 198–199CrossRef Google Scholar

Hillis, D M & Green, D M (1990) Evolutionary changes of heterogametic sex in the phylogenetic history of amphibians. Journal of Evolutionary Biology, 3, 49–64CrossRef Google Scholar

Holmgren, K & Mosegaard, H (1996) Implications of individual growth status on the future sex of the European eel. Journal of Fish Biology, 49, 910–925CrossRef Google Scholar

Hurst, L D (1994) Embryonic growth and the evolution of the mammalian Y chromosome. I. The Y as an attractor for selfish growth factors. Heredity, 73, 223–232CrossRef Google Scholar

Janvier P (1996a) Jawed vertebrates. In: D Maddison & W Maddison (eds) The Tree of Life, http://phylogeny.arizona.edu/tree/eukaryotes/animals/chordata/gnathostomata.html

Janvier P (1996b) Vertebrata. In: D Maddison & W Maddison (eds) The Tree of Life, http://phylogeny.arizona.edu/tree/eukaryotes/animals/chordata/vertebrata.html

Janzen, F J (1992) Heritable variation for sex ratio under environmental sex determination in the common snapping turtle (Chelydra serpentina). Genetics, 131, 155–161Google Scholar

Janzen, F J & Paukstis, G L (1991a) Environmental sex determination in reptiles: ecology, evolution, and experimental design. The Quarterly Review of Biology, 66, 149–179CrossRef Google Scholar

Janzen, F J & Paukstis, G L (1991b) A preliminary test of the adaptive significance of environmental sex determination in reptiles. Evolution, 45, 435–440CrossRef Google Scholar

Jiménez, R, Sanchez, A, Burgos, M & Díaz, Guardia R (1996) Puzzling out the genetics of mammalian sex determination. Trends in Genetics, 12, 164–166CrossRef Google Scholar PubMed

Johnston, C M, Barnett, M & Sharpe, P T (1995) The molecular biology of temperature-dependent sex determination. Philosophical Transactions of the Royal Society of London, series B, 350, 297–303CrossRef Google Scholar PubMed

Jones, K W & Singh, L (1981) Conserved repeated DNA sequences in vertebrate sex chromosomes. Human Genetics, 58, 46–53CrossRef Google Scholar PubMed

Jones, K W & Singh, L (1985) Snakes and the evolution of sex chromosomes. Trends in Genetics, 1, 55–61CrossRef Google Scholar

Karlin S & Lessard S (1986) Theoretical Studies on Sex Ratio Evolution. Princeton, NJ: Princeton University Press

King, M & Rofe, R (1976) Karyotypic variation in the Australian gekko Phyllodactylus marmoratus (Gray) (Gekkonidae: Reptilia). Chromosoma, 54, 75–87CrossRef Google Scholar

Koehler, M R, Neuhaus, D, Engel, W, Schartl, M & Schmid, M (1995) Evidence for an unusual ZW/ZW'/ZZ sex-chromosome system in Scardinius erythrophtalmus (Pisces, Cyprinidae), as detected by cytogenetic and H-Y-antigen analyses. Cytogenetics and Cell Genetics, 71, 356–362CrossRef Google Scholar

Komdeur, J, Daan, S, Tinbergen, J & Mateman, C (1997) Extreme adaptive modification in sex ratio of the Seychelles warbler's eggs. Nature, 385, 522–525CrossRef Google Scholar

Koopman, P, Gubbay, J, Vivian, N, Goodfellow, P & Lovell-Badge, R (1991) Male development of chromosomally female mice transgenic for Sry. Nature, 351, 117–121CrossRef Google Scholar PubMed

Kraak, S B M & Looze, E M A (1993) A new hypothesis on the evolution of sex determination in vertebrates: big females ZW, big males XY. Netherlands Journal of Zoology, 43, 260–273CrossRef Google Scholar

Kraak SBM, Pen I & Weissing FJ (2000) Joint evolution of environmental and genetic sex determination. In: I Pen Sex Allocation in a Life History Context, pp 149-160. Ph.D. thesis University of Groningen (http://www.biol.rug.nl/theobio/main/research/ido/bsex\_rat.htm)

Kusz, K, Kotecki, M, Wojda, A, Jaruzelska, J, Szarras-Czapnik, M, Ruszczynska-Wolska, A, Latos-Bielenska, A & Warenik-Szymankiewicz, A (1999) Incomplete masculinisation of XX subjects carrying the SRY gene on an inactive X chromosome. Journal of Medical Genetics, 36, 452–456Google Scholar PubMed

Lagomarsino, I V & Conover, D O (1993) Variation in environmental and genotypic sex-determining mechanisms across a latitudinal gradient in the fish, Menidia menidia. Evolution, 47, 487–494CrossRef Google Scholar PubMed

Larson, A & Dimmick, W W (1993) Phylogenetic relationships of the salamander families: an analysis of congruence among morphological and molecular characters. Herpetological Monographs, 7, 77–93CrossRef Google Scholar

Laurin M (1996) Terrestrial vertebrates. In: D Maddison & W Maddison (eds) The Tree of Life, http://phylogeny.arizona.edu/tree/eukaryotes/animals/chordata/terrestrial\_vertebrates.html

Laurin, M & Reisz, R R (1995) A reevaluation of early amniote phylogeny. Zoological Journal of the Linnean Society, 113, 165–223CrossRef Google Scholar

Laurin M, Gauthier JA & Hedges SB (1996) Amniota. In: D Maddison & W Maddison (eds) The Tree of Life, http://phylogeny.arizona.edu/tree/eukaryotes/animals/chordata/amniota.html

Lundberg JG (1996) Actinopterygii. In: D Maddison & W Maddison (eds) The Tree of Life, http://phylogeny.arizona.edu/tree/eukaryotes/animals/chordata/actinopterygii/actinopterygii.html

Mahony, M J (1991) Heteromorphic sex-chromosomes in the australian frog Crinia bilingua (Anura, Myobatrachidae). Genome, 98, 334–337CrossRef Google Scholar

Maistro, E L, Mata, E P, Oliveira, C & Foresti, F (1998) Unusual occurrence of a ZZ/ZW sex-chromosome system and supernumerary chromosomes in Characidium cf. fasciatum (Pisces, Characiformes, Characidiinae). Genetica, 104, 1–7CrossRef Google Scholar

Marín, I & Baker, B S (1998) The evolutionary dynamics of sex determination. Science, 281, 1990–1994Google Scholar PubMed

Maynard, Smith J & Stenseth, N C (1978) On the evolutionary stability of the female biased sex ratio in the wood lemming (Myopus schisticolor): the effect of inbreeding. Heredity, 41, 205–214Google Scholar

McNamara, J M & Houston, A T (1996) State-dependent life histories. Nature, 380, 215–221CrossRef Google Scholar PubMed

McVean, G & Hurst, L D (1996) Genetic conflicts and the paradox of sex determination: three paths to the evolution of female intersexuality in a mammal. Journal of Theoretical Biology, 179, 199–211CrossRef Google Scholar

Mittwoch, U (1971) Sex determination in birds and mammals. Nature, 231, 432–434CrossRef Google Scholar PubMed

Mittwoch, U (1986) Males, females and hermaphrodites. Annals of Human Genetics, 50, 103–121CrossRef Google Scholar PubMed

Mittwoch, U (1989) Sex differentiation in mammals and tempo of growth: probabilities vs. switches. Journal of Theoretical Biology, 137, 445–455CrossRef Google Scholar PubMed

Mittwoch, U (1996a) Genetics of sex determination: an overview. Advances in Genome Biology, 4, 1–28CrossRef Google Scholar

Mittwoch, U (1996b) Unilateral phenotypic manifestations of bilateral structures: which phenotype matches the genotype?Frontiers in Endocrinology, 16, 121–129Google Scholar

Mittwoch, U (1996c) Sex-determining mechanisms in animals. Trends in Ecology and Evolution, 11, 63–67CrossRef Google Scholar

Mittwoch, U, Delhanty, J D A & Beck, F (1969) Growth of differentiating testes and ovaries. Nature, 224, 323–325CrossRef Google Scholar PubMed

Molino, W F, Schmid, M & Galetti, P M (1998) Heterochromatin and sex chromosomes in the Neotropical fish genus Leporinus (Characiformes, Anastomidae). Cytobios, 94, 141–149Google Scholar

Moreira-Filho, O, Bertollo, L A C & Galetti, P M Jr (1993) Distribution of sex chromosome mechanisms in neotropical fish and a description of a ZZ/ZW system in Parodon hilarii (Parodontidae). Caryologia, 46, 115–125CrossRef Google Scholar

Moritz C (1990) Patterns and processes of sex chromosome evolution in gekkonid lizards (Sauria: Reptilia). In: E Olmo (ed) Cytogenetics of Amphibians and Reptiles, pp 205–220. Basel: Birkhäuser Verlag

Nakamura, D, Wachtel, S S, Lance, V & Beçak, W (1987) On the evolution of sex determination. Proceedings of the Royal Society of London, series B, 232, 159–180CrossRef Google Scholar PubMed

Nanda, I, Schartl, M, Feichtinger, W, Epplen, J T & Schmid, M (1992) Early stages of sex chromosome differentiation in fish as analysed by simple repetitive DNA sequences. Chromosoma, 101, 301–310CrossRef Google Scholar PubMed

Nelson J S (1994) Fishes of the World, 3rd edn. New York: John Wiley & Sons

Nur, U (1974) The expected changes in the frequency of alleles affecting the sex ratio. Theoretical Population Biology, 5, 143–147CrossRef Google Scholar PubMed

Olmo E (1986) Animal Cytogenetics, volume 4, Chordata 3, A, Reptilia. Berlin: Gebrüder Borntraeger

Olmo E, Odierna G, Capriglione T & Cardone A (1990) DNA and chromosome evolution in lacertid lizards. In: E Olmo (ed) Cytogenetics of Amphibians and Reptiles, pp 181–204. Basel: Birkhäuser Verlag

Packard GC (1991) Egg incubation: its effects on embryonic development in birds and reptiles. In: D C Deeming & M W J Ferguson (eds) Egg Incubation: Its Effects on Embryonic Development in Birds and Reptiles, pp 213–228. Cambridge: Cambridge University Press

Packard, G C, Packard, M J & Birchard, G F (1989) Sexual-differentiation and hatching success by painted turtles incubating in different thermal and hydric environments. Herpetologica, 45, 385–392Google Scholar

Page, D C, Mosher, R, Simpson, E M, Fisher, E M C, Mardon, G, Pollack, J, McGillivray, B, , Chapelle A & Brown, L G (1987) The sex determining region of the human Y chromosome encodes a finger protein. Cell, 51, 1091–1104CrossRef Google Scholar PubMed

Palmer, M S, Sinclair, A H, Berta, P, Ellis, N A, Goodfellow, P N, Abbas, N E & Fellous, M (1989) Genetic evidence that ZFY is not the testis-determining factor. Nature, 342, 937–939CrossRef Google Scholar

Patiño, R, Davis, K B, Schoore,, J E, Uguz, C, Strüssman, C A, Parker, N C, Simco, B A & Goudi, C A (1996) Sex differentiation of channel catfish gonads: normal development and effects of temperature. Journal of Experimental Zoology, 276, 209–2183.0.CO;2-R>CrossRef Google Scholar

Pieau, C (1975) Effets des variations thermique sur la différentiation du sexe chez les vertébrés. Bulletin du Société Zoologique Français, 100, 67–76Google Scholar

Price DJ (1984) Genetics of sex determination in fishes – a brief review. In: G W Potts & R J Wootton (eds) Fish Reproduction, pp 77–89. London: Academic Press

Raymond, S C, Parker, E D, Kettlewell, J R, Brown, L G, Page, D C, Kusz, K, Jaruzelska, J, Reinberg, Y, Flejter, W L, Bardwell, V J, Hirsch, B & Zarkower, D (1999) A region of human chromosomes 9p required for testis development contains two genes related to known sexual regulators. Human Molecular Genetics, 8, 989–996CrossRef Google Scholar PubMed

Rice, W R (1987) The accumulation of sexually antagonistic genes as a selective agent promoting the evolution of reduced recombination between primitive sex chromosomes. Evolution, 41, 911–914CrossRef Google Scholar PubMed

Richards, C M & Nace, G W (1978) Gynogenetic and hormonal sex reversal used in tests of the XX-XY hypothesis of sex determination in Rana pipiens. Growth, 42, 319–332Google Scholar

Rieppel O (1988) The classification of the Squamata. In: M J Benton (ed) The Phylogeny and Classification of the Tetrapods, volume 1, Amphibians, Reptiles, Birds, pp 261–293. Oxford: Clarendon Press

Roldan, E R S & Gomiendo, M (1999) The Y chromosome as a battle ground for sexual selection. Trends in Ecology and Evolution, 14, 58–62CrossRef Google Scholar

Römer, U & Beisenhertz, W (1996) Environmental determination of sex in Apistogramma (Cichlidae) and two other freshwater fishes (Teleostei). Journal of Fish Biology, 48, 714–725Google Scholar

Schmid M & Haaf T (1989) Origin and evolution of sex chromosomes in Amphibia: the cytogenetic data. In: S S Wachtel (ed) Evolutionary Mechanisms in Sex Determination, pp 37–56. Boca Raton, FL: CRC Press, Inc

Schmid, M, Steinlein, C, Feichtinger, W, Almeida, C G & Duellman, W E (1988) Chromosome banding in Amphibia, XIII. sex chromosomes, heterochromatin and meiosis in marsupial frogs (Anura, Hylidae). Chromosoma, 97, 33–42CrossRef Google Scholar

Schmid, M, Steinlein, C & Feichtinger, W (1992) Chromosome-banding in Amphibia. 17. 1st demonstration of multiple sex-chromosomes in amphibians – Eleutherodactylus maussi (Anura, Leptodactylidae). Chromosoma, 101, 284–292CrossRef Google Scholar

Schmid, M, Ohta, S, Steinlein, C & Guttenbach, M (1993) Chromosome-banding in Amphibia. 19. Primitive ZW/ZZ sex chromosomes in Buergeria buergeri (Anura, Rhacophoridae). Cytogenetics and Cell Genetics, 62, 238–246CrossRef Google Scholar

Scudo, F M (1967) Criteria for the analysis of multifactorial sex determination. Monitore Zoologia Italia (N. S.), 1, 1–21Google Scholar

Shine, R (1999) Why is sex determined by nest temperature in many reptiles?Trends in Ecology and Evolution, 14, 186–189CrossRef Google Scholar PubMed

Sinclair, A H, Berta, P, Palmer, M S, Hawkins, J R, Griffiths, B L, Smith, M J, Foster, J W, Frischauf, A M, Lovell-Badge, R & Goodfellow, P N (1990) A gene from the human sex-determining region encodes a protein with homology to a conserved DNA-binding motif. Nature, 346, 240–244CrossRef Google Scholar PubMed

Singh, L & Jones, K W (1982) Sex reversal in the mouse (Mus musculus) is caused by a recurrent nonreciprocal crossover involving the X and an aberrant Y chromosome. Cell, 28, 205–216CrossRef Google Scholar PubMed

Smith, C A & Joss, J M P (1994) Sertoli cell differentiation and gonadogenesis in Alligator mississippiensis. The Journal of Experimental Biology, 270, 57–70Google Scholar

Sola, L, Cataudella, S & Capanna, E (1981) New developments in vertebrate cytotaxonomy III. Karyology of bony fishes: a review. Genetica, 54, 285–328CrossRef Google Scholar

Strüssman, C A, Cota, J C C, Phonlor, G, Higuchi, H & Takashima, F (1996a) Temperature effects on sex-differentiation of 2 South-American atherinids, Odontesthes argentinensis and Patagonia hatcheri. Environmental Biology of Fishes, 47, 143–154CrossRef Google Scholar

Strüssman, C A, Moriyama, S, Hanke, E F, Cota, J C C & Takashima, F (1996b) Evidence of thermolabile sex determination in pejerrey. Journal of Fish Biology, 48, 643–651CrossRef Google Scholar

Tiersch, T R, Mitchell, M J & Wachtel, S S (1991) Studies on the phylogenetic conservation of the SRY gene. Human Genetics, 87, 571–573CrossRef Google Scholar PubMed

Trivers, R L & Willard, D E (1973) Natural selection of parental ability to vary the sex ratio of offspring. Science, 179, 90–92CrossRef Google Scholar PubMed

Valleley, E M A, Muller, U, Ferguson, M W J & Sharpe, P T (1992) Cloning and expression analysis of two ZFY-related zinc finger genes from Alligator mississippiensis, a species with temperature-dependent sex determination. Gene, 119, 221–228CrossRef Google Scholar PubMed

VanEenennaam, A L, VanEenennaam, J P, Medrano, J F & Doroshov, S I (1999) Evidence of female heterogametic sex determination in white sturgeon. Journal of Heredity, 90, 231–233CrossRef Google Scholar

Viets, B E, Ewert, M A, Talent, L G & Nelson, C E (1994) Sex-determining mechanisms in squamate reptiles. The Journal of Experimental Zoology, 270, 45–56CrossRef Google Scholar

Volobouev, V, Pasteur, G, Bons, J, Guillaume, C P & Dutrillaux, B (1990) Sex-chromosome evolution in reptiles – divergence between 2 lizards long regarded as sister species, Lacerta vivipara and Lacerta andreansky. Genetica, 83, 85–91Google Scholar

Wellins, D J (1987) Use of an H-Y antigen assay for sex determination in sea turtles. Copeia, 1987, 46–52CrossRef Google Scholar

Werren, J H & Beukeboom, L W (1998) Sex determination, sex ratios and genetic conflict. Annual Review of Ecology and Systematics, 29, 233–261CrossRef Google Scholar

Winge, ⌀ (1932) The nature of sex chromosomes. Proceedings of the 6th International Congress of Genetics, 1, 343–355Google Scholar

Witschi, E (1929) Studies on sex differentiation and sex determination in amphibians. III. Rudimentary hermaphroditism and Y chromosome in Rana temporaria. The Journal of Experimental Zoology, 54, 157–223CrossRef Google Scholar

Yntema, C L (1976) Effects of incubation temperatures on sexual differentiation in the turtle, Chelydra serpentina. Journal of Morphology, 150, 453–462CrossRef Google Scholar

Yntema, C L (1979) Temperature levels and periods of sex determination during incubation of eggs of Chelydra serpentina. Journal of Morphology, 159, 17–28CrossRef Google Scholar

Zaborski, P, Dorizzi, M & Pieau, C (1982) H-Y antigen expression in temperature sex reversed turtles Emys orbicularis. Differentiation, 22, 73–78CrossRef Google Scholar PubMed

Zaborski, P, Dorizzi, M & Pieau, C (1988) Temperature-dependent gonadal differentiation in the turtle Emys orbicularis: concordance between sexual phenotype and serological H-Y antigen expression at threshold temperature. Differentiation, 38, 17–20CrossRef Google Scholar PubMed