Specific subject-matter question

[Jose rubio]

Hi all,

I have a quick question regarding a subject but I am not sure how to go about this. Is there a specific thread to post this type of questions?

Here is my original question:

What is the difference or relationship between Homeobox (Hox) and Paired box (Pax)?

Here is what I know:

* Both Hox and Pax have to do with embryo development regarding body segmentation
* Hox consist of approximately 60 amino acids, whereas Pax consists of 128 amino acids
* Mutations on Pax result in malformation, whereas mutations on Hox result in synpolydactyly and brachydactyly

I am a bit confused on the relationship between the two.

Any guidance will be greatly appreciated. (and don't be rude)

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[Naruhodo]

Hi there Jose,

This is probably way too late to be useful to you, but I thought I'd give it a shot anyway. Homeobox genes, originally discovered in drosophila, have to do with laying out body segment patterning. You may have seen pictures of flies with legs in the position they would normally have antenna (antennapedia), which is an example of a homeobox mutant. A neat thing about homeobox genes in several species is that their chromosomal order seems to correspond in many cases to the order in which they are expressed along the anterior-posterior axis of the organism. How cool is that?

Pax genes on the other hand tend to be tissue-specific transcription factors. Mutations in these genes also have developmental consequences, but they are often restricted to the tissues where that particular transcription factor plays a key role. Mutations of PAX6 for examples cause isolated aniridia, or the lack of an iris. Pax3 on the other hand plays roles in several tissues and mutations in this gene are a cause of Waardenburg sysndrome, a condition characterized by pigmentary changes in the eyes, hair, or skin, hearing loss, and telecanthus.

The tricky part of answering your question is that although they are named due to a common domain structure, it is difficult to generalize too much about what all homeobox or all paired box genes do. Depending on what you need the information for, you might be better off learning about individual genes and their specific roles in development.

Best of luck!