Two genes interact to produce various phenotypic ratios ...

Question

Two genes interact to produce various phenotypic ratios among F₂ progeny of a dihybrid cross. Design a different pathway explaining each of the F₂ ratios below, using hypothetical genes R and T and assuming that the dominant allele at each locus catalyzes a different reaction or performs an action leading to pigment production. The recessive allele at each locus is null (loss-of-function). Begin each pathway with a colorless precursor that produces a white or albino phenotype if it is unmodified. The ratios are for F₂ progeny produced by crossing wild-type F₁ organisms with the genotype RrTt.

9/16 red : 7/16 white

Accepted Answer

Hello, everyone. Here's our next question. It says the blank mutation is a type of gain of function mutation in which novel gene activities are acquired. So again, of function mutation, we recall occurs when the mutation causes the gene mutates in such a way that it causes the protein it codes for to have increased activity or even a totally new function. In this case, our questions asking about a novel gene activity. So new function, let's look at our answer choices and we'll discover as we look over them that here's a time when it's very useful to be familiar with some scientific prefixes and words and what they mean because when we're maybe not quite sure of an answer that can really help us zoom in on the correct choice. Choice. A says hyper, more fick. So here we have the prefix hyper, you can think of it as meaning high and like I think of a hyper child high activity level. So hyper more fic mutation leads to a higher level of activity. So that's not quite what we're looking for. That is one type of a gain of function mutation. But we're looking for a completely new activity. So choice A isn't quite the right thing we're looking for. Then choice B is high polymorphic. Well, if we always remember that hyper and hypo are opposed to each other, and if we remember hyper, like a hyper child means higher, hypo means low. So hyper, more fick, excuse me hypo morph IQ is not a gain of function mutation. This is a loss, a function mutation that leads to lower protein or gene activity. So that's why that's not our correct answer. Choice. C says a more fick. Well, that a prefix means without. So this would be a total loss of function mutation. The protein no longer functions at all that the gene codes for or the gene is so mutated, it can't code for the protein. So that's why choice C is not correct. Finally, we're down to choice D which says Neo, more fake. Well, Neo means new and this does indeed cause novel gene activities if you have a neo, more fick mutation. So choice D nia more fick is our answer. The nea morphing mutation is a type of gain of function mutation in which novel gene activities are acquired. See you in the next video.

My Courses

Chemistry

Biology

Math

Physics

Business

Social Sciences

Programming

Product & Marketing