what difference would there be in the product cells at telophase II of the meiosis if there had been one crossing over at a position half way betwwen the huntington disease gene and the centromere from one pair of autosomes (chromosome 4)has a short arm and a long arm on the short arm is a gene for huntingtons disease (H) AND ON THE LONG ARM is a gene for red hair(R) please can u help ,
Posted by jane on Monday, March 26, 2007 at 4:05am.
what difference would there be in the product cells at telophase II of the meiosis if there had been one crossing over at a position half way betwwen the huntington disease gene and the centromere from one pair of autosomes (chromosome 4)has a short arm and a long arm on the short arm is a gene for huntingtons disease (H) AND ON THE LONG ARM is a gene for red hair(R) please can u help ,
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To understand the potential differences in the product cells at telophase II of meiosis due to crossing over, we need to review the basics of meiosis and crossing over.
Meiosis is a type of cell division that produces gametes (sperm and eggs) with half the number of chromosomes as the parent cell. It involves two rounds of division: meiosis I and meiosis II. During meiosis I, homologous chromosomes pair up and exchange genetic material through a process called crossing over.
Crossing over occurs between homologous chromosomes, which are similar but not identical chromosomes inherited from the parents. It involves the exchange of genetic material between chromatids, the replicated strands of DNA within a chromosome. Crossing over contributes to genetic diversity by creating new combinations of alleles on each chromosome.
Now let's apply this knowledge to the specific scenario you provided. You mentioned a pair of autosomes (chromosome 4) with a short arm and a long arm. On the short arm is a gene for Huntington's disease (H), and on the long arm is a gene for red hair (R). We also need to consider that there is one crossing over event halfway between the Huntington disease gene and the centromere.
During meiosis I, homologous chromosomes pair up, and crossing over occurs between chromatids at a specific position. In our case, the crossing over event happens halfway between the Huntington disease gene and the centromere.
As a result of crossing over, two chromatids exchange genetic material. Let's consider a possible outcome:
Before crossing over:
- Chromatid 1: Short arm (H) - Long arm (R)
- Chromatid 2: Short arm (H) - Long arm (R)
After crossing over:
- Chromatid 1: Short arm (H) - Long arm (R)
- Chromatid 2: Short arm (H) - Long arm (R)
In this scenario, crossing over did not result in a change in the genetic material on either chromatid. Both chromatids retained the same combination of alleles before and after crossing over.
Therefore, at telophase II of meiosis, the product cells would still have the same genetic information as before crossing over. The Huntington disease gene (H) would still be present on the short arm, and the red hair gene (R) would still be present on the long arm.
It's important to note that this is just one possible outcome, and the actual outcome of crossing over can vary. The specific location and probability of crossing over events are influenced by factors such as genetic distance and recombination rates.