An inversion heterozygote has one chromosome with the following linkage arrangem

Question

An inversion heterozygote has one chromosome with the following linkage arrangement:

The other chromosome possesses an inversion that spans genes c, d, e, and f.

            a. What type of inversion is it?

            b. Draw the configuration of these chromosomes at synapsis.

            c. If a four-strand double crossover occurs in the areas c-d and e-f, what are the meiotic product?

            d. Repeat for a three-strand double crossover in these regions.

            e. Will any of the meiotic products have a normal karyotype? Explain.

for my answers i got:

chromsome 1: abcdcg

chromsome 2: abcdeedcg

chromsome 3: abffg

chromsome 4: gcdefg

could anyone verify these?

Explanation / Answer

1.This is paricentric inversion because this involves centromere.

2.ABG.FEDC

There must be inversion of GFEDC and the result is .ABCDEFG

3. ABCDEFG

ABCDEFG

there is cross over between CD and EF

therefore result will be:

ABDCFEG, ABDCEFG,ABCDFEG,ABCDEFG

4. In three strand crossover the meiotic product will be of parental type because the third strand will revert it.

5. Yes, tere will be normal karyotype among them. Because three strand crossover do not form recombinants as the third strabd when cross over it will revert back the inversion and form normal parental strand.

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