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| | ETI - Turtles of the World: Temperature-dependent sex determination |
 | | With the exception of the genera Platemys (XY, Chelidae), Staurotypus (XY, Kinosternidae), and Siebenrockiella (XY) and Kachuga smithii (ZW) (Bataguridae), turtles lack heteromorphic sex chromosomes (either XY male heterogamety, or ZW female heterogamety); their mechanism for sex determination is different than in humans. |
 | | Pattern I, found in some Bataguridae, and the Carettochelyidae, Cheloniidae, Dermochelyidae, Emydidae, and Testudinidae, has a single transition zone of temperature below which incubation yields nearly or totally 100% males and above which only females are produced. |
 | | Pattern I occurs chiefly in turtles in which the adult females are larger than adult males; Pattern II is found mainly in turtles with females smaller than males or in which body size is not dimorphic. |
| www.eti.uva.nl /Turtles/Turtles2a.html (204 words) |
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