Type A1B brachydactyly (short middle phalanges) is a genetically determined trait that maps to the short arm of chromosome 5 in humans. If you classify individuals as either having or not having brachydactyly, the trait appears to follow a single-locus, incompletely dominant pattern of inheritance. However, if one examines the fingers and toes of affected individuals, one sees a range of expression from extremely short to only slightly short. What might cause such variation in the expression of brachydactyly?

Video transcript

Welcome back. Here's our next question. It says bracketed actually is a genetic condition characterized by shortened fingers and toes. Which of the following is a possible genetic mode of inheritance inheritance for bracket actually, well actually can actually be caused by mutations in a couple of different genes with different patterns of inheritance. But the most common mode of inheritance for the most common form of productively is choice be autism will dominant. So the other answer choices are just that's not the most common pattern. It's not usually associated as with excellent recessive inheritance um Or autism or recessive inheritance. Um Just a little note about choice. C. Y link. There's very very few things that are Y linked um since only males have the Y chromosome. And it's this tiny little chromosome with not much on it. Um There's not a lot of conditions that are Y linked. So we're going to cross that off. So if you ever had to guess, that would probably be one that you most often would eliminate unless you knew or something particular associated with males that does have S. R. Y. Gene determining male phenotype. So again, back and actually, which of the following is a possible genetic mode of inheritance. Choice be autism will dominant. See you in the next video