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Discussion Starter · #1 · (Edited)
Hi there.

I thought albino was simple recessive until trying to breed some...

-I bred a male litoria aurea (green frog, wild caught) to an albino female l. aurea. All the eggs were white but tadpoles normal colour.
-When the progeny of the above breeding are bred to each other, they are producing normal looking eggs and tadpoles.
-Yet when the progeny are bred back to the original female albino. All the eggs are white (as oppose to the normal black and white), but only around 25% are albino, and of the few albino frogs produced thus far (less than 20 -from hundreds of tadpoles- due to scoliosis/deformities) all appear to be male so maybe hinting to a sex linked trait.

Any idea as to what's going on here? :D
 

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Assuming its a single gene thats controlling this albinism(which it might not be) then your albino is homozygous recessive, and your other frog is homozygous dominant.
All original offspring would then be heterozygous for the trait, producing no albinos.
crossing those offspring to each other results in 25%homozygous dominant(normal looking) 50 percent heterozygous(normal looking but carrying the recessive gene) and 25 %hmozygous recessive(albino) Just because the probability of albinism is there doesnt mean every clutch will result in any albinism.
The results of taking these offspring and crossing back to your original albino female depends on what trait the individual offspring carried. If it is heterozygous, then theres a 50%chance of albinism.
This is all simple punet square type calculation, assuming the albinism is a single gene controlled trait, which it very well might not be. As far as the white eggs vs normal eggs, Im not sure whats going on there, especially if the white eggs produce normal offspring.
 

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If you are seeing a lot of deformation in the metamorphs then you should consider changing the supplements used when feeding the adults as this is good indicator of insufficient supplementation in the adults (usually insufficient vitamin A as retinyl palmitate).


Ed
 

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I think you're seeing the way the odds play out........

In a perfect world, you'd see results play out like a punnet square.......However, in the real world, the results may be very different.......

I'd suspect if you were to keep breeding the Het F1's together, you'd eventaully end up with Albinos at some point........Some pairings seem to give better odds/results than others, and you just have to find those pairings.........

It isn't odd at all to see a skewed sex ratio when your dealing with low production numbers.......Once those numbers rise, you'll find both sexes......You'll also find some years you may be Female heavy and vice versa, and some pairings can have a tendency to produce one sex or another.......
 

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Hypopigmentation in general and albinism in particular can be caused by mutations in or inactivation of one of several genes that regulate melanin synthesis and melanocyte differentiation. There are null alleles (resulting for example in the complete lack of tyrosinase activity; tyrosinase is an enzyme required for melanin synthesis) and hypomorphic alleles that retain some level of activity. Given the complexity of the genetics at hand it is not surprising that you are not observing Mendelian ratios. If you would like to read more on this I can send you a review but unless you can genotype your frogs you'll probably have to keep experimenting. Given the low morph rate of your albinos there seems to be a strong selection against that phenotype, so I'm not sure this is something worth continuing (unless this is part of a scientific experiment).
 

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Discussion Starter · #6 ·
I would be interested in reading any reviews. Thank you.

May have to look into genotype. I have a contact who works in a lab doing Sequencing and Genotyping, maybe I should ask him what they could do (tbh I don't understand what genotype/sequencing is).

I just want to try gain an understanding of what is going on with this mutation in this particular species of frog.
 

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A genotype (noun) refers to a specific DNA sequence (or, more broadly, to a specific version of a gene or trait); to genotype (verb) is scientific jargon and means to determine the presence or variant of a genotype by standard molecular biology methods (DNA sequencing is one of them). Let's say albinism were caused by a recessive mutation a in a single gene A on an autosomal chromosome, then there would be three different possible genotypes, only one of which results in albinism:
Genotype Phenotype
AA wildtype
Aa wildtype
aa albino
While some forms of hypopigmentation may follow this simple scheme others don't, so you'd have to consider the status of genes B, C, D, etc as well. For many genes and mutations, it's not black and white either (A or a). If A=100% and a=0% activity there could be anything in between depending on the type of mutation. Give me your email (mail to [email protected]) and I'll forward the review on albinism. There's a syndrome in Xenopus called periodic albinism but it's the opposite of what you are seeing: the eggs are pigmented and turn white during tadpole development
 
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