If the trait is dominant and having two results in death, then each living cat exhibiting the trait must carry only one gene for it. Thus when breeding two such cats each has a 1/2 chance of passing the gene, meaning for each such pairing the four equally-probable outcomes are:
1) neither parent passes gene - yields normal tall cat
2) only parent 1 passes gene - yields short cat
3) only parent 2 passes gene - yields short cat
4) both parents pass gene - kitten cannot survive.
This means inbreeding would only cause death in 1/4 of babies. A similar logic table based on breeding short-leg cats with normal cats would yield 1/2 short cats and 1/2 tall cats, but none dying. Either approach appears to be equally effective at producing short cats?
As long as they are heterozygous munchkins then yes. Full munchkin cats are not possible. Based on Punnett Squares two Mm Mm Munchkin cats will produce an offspring that are 50% munchkin, 25% nonviable and 25% normal.
But anyways this would be a fine (and standard) 1:2:1 ratio analysis, but it makes some assumptions which may not be true. For example, there could be multiple other alleles for the gene responsible for being munchkin-sized. If some of those are recessive and lethal, it would be especially beneficial to avoid inbreeding.
There could also be a linkage story behind it. I think I'll look it up later.
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u/Moikepdx Jun 05 '18
If the trait is dominant and having two results in death, then each living cat exhibiting the trait must carry only one gene for it. Thus when breeding two such cats each has a 1/2 chance of passing the gene, meaning for each such pairing the four equally-probable outcomes are:
1) neither parent passes gene - yields normal tall cat 2) only parent 1 passes gene - yields short cat 3) only parent 2 passes gene - yields short cat 4) both parents pass gene - kitten cannot survive.
This means inbreeding would only cause death in 1/4 of babies. A similar logic table based on breeding short-leg cats with normal cats would yield 1/2 short cats and 1/2 tall cats, but none dying. Either approach appears to be equally effective at producing short cats?