KAPLAN BIO QUESTION

[kfcman289]

I had a kaplan bio question that was essentially an experiment with yeast that did not have a centromere. Suprisingly, the passage states that the yeast were actually able to divide without a centromere, but that dna would not be equally distributed so the cells that did not have the DNA would die out? Can cell division actually occur without centromeres for microtubles to attach to?

Thanks.

---

Members don't see this ad.

 

[labqi]

I guess so. Division is a property of the actin filaments. Whether each cell gets the correct genetic information is another story as that I believe depends on the microtubules. Please correct me if I'm wrong.

 

[StIGMA]

In a normal cell you would likely activate a cell death program (G2/M phase arrest). This is a theoretical question ignoring other cell complexities- what happens to chromosomes in a dividing cell without centromeres? Centromeres are where microtubules attach and are pulled toward the centrioles in an even split. Without this even split, daughter cells will have uneven chromosome complements (seen frequently in cancer, termed aneuploidy) and cells with toxic combinations of chromosomes die out. Cell division itself (telophase) is an actin-dependent process (cytokinesis, contractile ring), so theoretically cell division can occur without centromeres (or even DNA for that matter).

 

[dyspareunia]

Spoilers, MTs don't attach to the centromere. They attach to kinetochores, which I'll admit normally attach at the centromere. Centromere is DNA, kinetochores are proteins.

You can have kinetochores without centromeres. The only problem with no centromere is that sister chromatids aren't linked, so there is no way to guarantee equal division.