# frogs changing gender?



## Ruby Rue (Mar 21, 2008)

I've heard that if you have a group of frogs that if there is too many males/no females that the smallest male will gentically change from male form to female form??

How much truth is there in this theory?


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## Punchfish (Jun 13, 2008)

It happens in fish and according to Jurassic Park (amazing film lol) its possible in frogs, but I've never actually read anything that proves this to be true and what species.


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## Ruby Rue (Mar 21, 2008)

I googled it and started reading a paper on adding a hormone and it would change a certain japanese frog from male to female.


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## Pliskens_Chains (Jun 8, 2008)

i did hear that certain african species of frogs are capable of this but i have no idea which species it is.


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## sean k (Dec 20, 2007)

*frogs*

i have never heard of this but you never no.


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## Ruby Rue (Mar 21, 2008)

Change of the Heterogametic Sex From Male to Female in the Frog -- Ogata et al. 164 (2): 613 -- Genetics


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## boipevassu (Aug 6, 2007)

*Gender Bias*

That paper says that in different populations of frogs of the same species, in different parts of Japan, the genetic make-up of males and females is expressed in different ways.

In a human a male is 'heterogametic' containing X and Y chromosomes (XY) and a female is 'homogametic' (XX).

In the frog R.rugosa some populations have males as XY and females as XX.

Other populations have females as ZW and males as ZZ. So females are made by combining the gametes that are not the same in those populations.

Cross-breeding these different populations changes the ratios of males and females that are produced - but does not change the sex of a metamorphosed frog from male to female or vice versa once it has developed.

The effect of hormones on gender ratio and its reversal, and the existence of intersex frogs (with ovotestes and the potential to function as a male or female) is discussed in cricket frogs in this paper:

Forms and Prevalence of Intersexuality and Effects of Environmental Contaminants on Sexuality in Cricket Frogs (Acris crepitans)

This paper talks about the 'gonadal feminization' of frogs including Xenopus and Rana rugosa by hormones:

Effects of Chinese Domestic Polychlorinated Biphenyls (PCBs) on Gonadal Differentiation in Xenopus laevis

In this case development of gonads is affected by the amount of contaminants in the water and the process is seen to happen in tadpoles.



This is more frightening:

BBC News | HEALTH | Tracking sex hormone pollution

It describes the possible effects of sex hormones in our rivers and possibly drinking water - it might not just be aquatic organisms that are being affected! 

Bottled water might be the way forward!


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