Some stickleback fish develop protective spines, and other stickl...

Question

Some stickleback fish develop protective spines, and other stickleback fish are spineless. Spine development is controlled by the expression of a gene known as Pitx1. The spineless phenotype is due to a mutation in Pitx1 that results in no expression of Pitx1 during development in regions where spines would otherwise form. When scientists compared the Pitx1 coding sequence in spined and spineless fish, they found this sequence was the same in both types of fish. Propose plausible hypotheses for the location of this mutation and for how it alters spine development.

Accepted Answer

Welcome back. Here's our next problem. It says a mexican cave fish spends its entire life in the dark with no need for vision. Scientists recently discovered that a mutation in the cave fish gene Sista thiamine beta synthesis A. Or C. B. S. A. Inhibits the blood flow to the cave fish's eyes during its development as an embryo. Which is the which of the following is a result of this mutation. Let's look through our answer choices. And we see that choice A says underdevelopment of the eyes which results in loss of vision and that is our correct answer with a restriction of blood flow during embryonic development. You don't have proper development of the eyes and therefore have a loss of vision. Again, since the cave fishes in the dark, that's not a problem. Uh Let's look through other answer choices though, Choice B. Says increased blood flow in all other parts of the body. The restriction of blood flow to one part of the body doesn't doesn't necessarily follow there's increased blood flow elsewhere. So that's not an answer. Choice C. Says death among the cave fish larvae know the cave fish are surviving just fine. So Choice see not her answer. And Choice D. Says deletion of the gene responsible for eyesight development among cave fish. Now the gene is not deleted, it's just mutated to restrict blood flow to the eyes. So no gene deletion. That's not our answer. So again which is the result of the mutation to the gene for eye development in cave fish. Choice a underdevelopment of the eyes which result in loss of vision, see you in the next video.

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