In Drosophila, loss-of-function Ultrabithorax mutations result in...

Question

In Drosophila, loss-of-function Ultrabithorax mutations result in the posterior thoracic segments differentiating into body parts with an identity normally found in the anterior thoracic segments. When the Ultrabithorax gene was cloned, it was shown to encode a transcription factor and to be expressed only in the posterior region of the thorax. Thus, Ultrabithorax acts to specify the identity of the posterior thoracic segments. Similar genes were soon discovered in other animals, including mice and humans. You have found that mice possess two closely related genes, Hoxa7 and Hoxb4, which are orthologs (see Genetic Analysis 14.2 for definition) of Ultrabithorax. You wish to know whether the two mouse genes act to specify the identity of body segments in mice.

How will you determine where and when the mouse genes are expressed?

Accepted Answer

Hi, everyone. Let's look at our next question. It says gene X and gene Y are closely related genes that have similar DNA sequences but are expressed in different regions of the developing nervous system and are known to play a role in nervous system development in mice. What experimental techniques would you use to identify the temporal and spatial patterns of expression of gene X and gene Y during mouse development, choice, A western blotting and Eliza choice B, southern and northern blotting choice C N C two hybridization and R N A sequencing and choice DPC R and DNA sequencing. So we're saying we're looking at two genes that are very closely related with similar sequences but are expressed in different regions in developing mice and saying what's the best way to look at where and when these genes are being expressed during mouse development? Well, the best technique for this is choice C in C two hybridization and R N A sequencing. The key is the N C because that means we're looking at expression in the tissues while they're intact and that allows you to map so that allows mapping of expression. And then of course R N A sequencing will be looking specifically for the gene that's expressed in that area. We'll look briefly at our other answer. Choices. Choice. A Western blog, a Eliza these use antibodies that are labeled to identify specific proteins that are present in a sample. So that allows you to identify that there are proteins present and how much perhaps but won't tell us a lot. It'll just say whether it's present or not. Uh It won't be as useful at finding out well, which anatomical structures of the mouse, which areas are they expressed in. So choice A is not going to be our correct answer. Choice B southern and northern blotting um using labeled C DNA probes to bind to DNA and R N A sequences DNA for Southern plotting and R N A for northern plotting. So again, that would tell you specifically I have gene X R N A or I have gene Y R N A or DNA in my sample. But again, if we're looking specifically to see how are the two expressed differently in different areas of the mouse and at different times, that's not going to be as useful as that in C two hybridization. So choice B not correct. And then finally, choice DPC R and DNA sequencing would be used to amplify and then identify the sequence of A DNA segment. But again, not going to give us that information on the temporal and spatial patterns of expression that we're looking for. So choice D is not our answer. So again, if we're looking for our two very similar genes, how are they expressed during development? Where and when the technique that's useful for that is choice C N C two hybridization and R N A sequencing. See you in the next video.

Key Concepts

Gene Expression

Transcription Factors

Orthologs

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