Translocation-What step in cell cyle?

[SaintJude]

In what phase of the cell cycle does chromosomal translocation occur?

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[chiddler]

my first thought was that the chromosomes must be heterochromatin in order for this to happen but...not necessarily, right? If anything heterochromatin makes it less likely to happen because it will be so hard for two DNA ends to find each other due to sterics. Whereas when they are spread out, DNA is all over the place so it becomes easier.

So if i'm correct then it would happen at any time, but more likely during any non mitotic phases. Additionally, the meotic metaphase would probably have some action going on, too.

If you look at these diseases associated with this, one is cancer (which means that this can occur in somatic cells, so is not exclusive to meiosis) and down syndrome + infertility (meosis).

 

[qtsjoe]

metaphase 1 (of meiosis)? Crossing over takes place and as a result parts of chromosomes are translocated between each other....?

 

[SaintJude]

Yes, translocation can be in meiosis but this is not just restricted to meisois b/c some translocations lead to cancer--which occurs in somatic cells.

And crossing-over & translocation are two different,separate processes!! (Just realized this myself recently)

Crossing-over is an exchange of genetic material between homologous chromosome
Chromosomal translocation exchange of genetic material between NONhomologous chromosomes

 

[chiddler]

oh good point

 

[SaintJude]

But, I do think you guys are right.

Chiddler, I think you're right on point. Read some research that verifies what you said. "Pathway is active during S and G2 phase when sister chromatids are readily available"

Also unlikely to be a discrete question:
Recent article from NEMJ says we don't understand timing too well
The cell-cycle timing of somatic chromosomal translocations in cancer remains poorly understood but may be relevant to their etiology and the mechanism of their formation.

It's kind of cool, that we just came up with a question people are actively studying in the lab...
Thanks!

 

[chiddler]

right on ;D good question is a thinking question