I recently bought a pair of Brown Bristlenose Ancistrus, they bred in the last week. But what puzzles me is although some fry are brown the rest are albino How has this occurred? What is the true colour of this species or are they a hybrid?
There is only them in the tank
Genetics?
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dw1305
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Re: Genetics?
Hi all,
We don't know quite what the origin of the Common Bristlenose ()) is, but your fry aren't hybrids. All your fish are"Common Bristlenoses", but some have a recessive gene for albinism.
It is most likely that the parents are both carriers of the same albino recessive gene (I'll call them all genes, rather than alleles & there is more than one albino mutation for the Common Bristlenose ()).
Your parents (F0) are heterozygous for genotype (Cc) and "wild type" for phenotype, we know this because they have produced albino off-spring, and albinism is a double recessive condition. I'll call the dominant and recessive genes "C" and "c". Your parent fish have the phenotype "wild type", and are brown, because the albino gene (c) is recessive to the gene for "wild type" colour (C). Both parents are "heterozygous" for pigment (melanin) production.
Assuming classical Mendelian inheritance (and it is an assumption, have a look here for more detail: (<http://www.planetcatfish.com/forum/view ... hp?t=35416>).), you should get 3:1 "wild type":albino phenotype in the off-spring (F1 generation).
This is because there are 4 possible options of genotype from the parents (the F0 generation) CC, Cc, cC and cc.
Fish with genotype "CC" will be homozygous for pigment, and their phenotype will be "wild type", Cc & cC will be heterozygous (like both parents) and "wild type", and only the double recessive re-combination "cc" will be homozygous for albinism, and albino.
You won't know the genotype of the "wild type" fry from their phenotype, but 2/3 will be heterozygous (Cc & cC), and 1/3 homozygous (CC).
cheers Darrel
We don't know quite what the origin of the Common Bristlenose ()) is, but your fry aren't hybrids. All your fish are"Common Bristlenoses", but some have a recessive gene for albinism.
It is most likely that the parents are both carriers of the same albino recessive gene (I'll call them all genes, rather than alleles & there is more than one albino mutation for the Common Bristlenose ()).
Your parents (F0) are heterozygous for genotype (Cc) and "wild type" for phenotype, we know this because they have produced albino off-spring, and albinism is a double recessive condition. I'll call the dominant and recessive genes "C" and "c". Your parent fish have the phenotype "wild type", and are brown, because the albino gene (c) is recessive to the gene for "wild type" colour (C). Both parents are "heterozygous" for pigment (melanin) production.
Assuming classical Mendelian inheritance (and it is an assumption, have a look here for more detail: (<http://www.planetcatfish.com/forum/view ... hp?t=35416>).), you should get 3:1 "wild type":albino phenotype in the off-spring (F1 generation).
This is because there are 4 possible options of genotype from the parents (the F0 generation) CC, Cc, cC and cc.
Fish with genotype "CC" will be homozygous for pigment, and their phenotype will be "wild type", Cc & cC will be heterozygous (like both parents) and "wild type", and only the double recessive re-combination "cc" will be homozygous for albinism, and albino.
You won't know the genotype of the "wild type" fry from their phenotype, but 2/3 will be heterozygous (Cc & cC), and 1/3 homozygous (CC).
cheers Darrel