The sex of many reptiles is known to be affected by
temperature. New research in the journal Genetics identifies the first gene
associated with temperature-dependent sex determination in any reptile. In
addition, variations or mutations at this gene contributes to geographic
differences in sex ratios by temperature. In certain reptile species, temperature
of an embryo can change if the sex of the embryo. An issue occurs however with
the quick climate change. For example, since global warming, many species such
as the painted turtle will only be able to produce one type of offspring. This
could potentially wipe out a species all together.
Since very little is known of temperature-dependent switch
between ovaries and testes is regulated, research from the University of North Dakota
used common snapping turtles to learn more on the subject. In previous work the
team identified that the male producing temperature is around 26.6 degrees Celsius
while female producing temperature is around 31 degrees celcius. The
researchers then located the gene CIRBP which is activated within 24 hours of
such a temperature shift. The study confirmed the CIRBP is expressed at the
right time and in the right place to be involved in sex specification. Next
researchers found snapping turtles from different climates and found that they
had different ratios in the sex determination when incubated at the same temperature.
Therefore, the team concludes that variation must account for the change in sex
ratios. However, researchers believe that CIRBP is not the only important gene
is specifying the sex of reptiles, more specifically snapping turtles. More
research needs to be done in order to provide more information on this sex
regulation gene or genes.
This is an interesting post. It's surprising how little of a temperature change can change the sex of the organism, and it will also be interesting to see how global warming will affect the population of turtles.
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ReplyDeleteI agree with Steve, but what I took from the post and article was that the sex-temperature relationship changes from time to time. So there is variation and the ratios change. If this didn't occur, I think the species would have gone extinct a long time ago.
ReplyDeleteThis actually brought to mind a tree we talked about in my bio class. The tree releases its seeds all the time, but every four years it releases an excess of them. This compensates for the seedlings lost to squirrel feedings. On that fourth year, the squirrels cannot possibly eat all the seeds it drops so this is when the majority of the tree population grows. If the trees did not do this, then the squirrel population would steadily grow until it outnumbered the amount of seeds the trees dropped, killing the species.
ReplyDeletenature is crazy
Its crazy how random mutations can be taken up into a popultaion just like the tree Betsy spoke about. However, without these mutations, natural selection would have killed off multiple species.
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