Explain how mitotic recombination leads to the mosaiccondition termed twin spots.

Variations in Chromosome NumberAneuploidy Describe the process of nondisjunction and explain when it takes place during cell division.

Chromosomal RearrangementsAre Caused by which factors?

In the experiment of Figure shown, Stern followed the inheritancepattern in which females carried two abnormal X chromosomesto correlate genetic recombination with the physical exchange ofchromosome pieces. Is it necessary to use a strain carrying twoabnormal chromosomes, or could he have used a strain in whichfemales carried one normal X chromosome and one abnormal Xchromosome with a deletion at one end and an extra piece of the Ychromosome at the other end?

A chromosome of genotype   C D recombines with a homolog of genotype   c d during meiosis when Spo11 produces a double-strand break between genes   C and   D. If anticrossover helicase disentangles the invading strand, the likely outcome would be             A)   two   C D and two   c d gametes.                      B)   two   C d and two   c D gametes.            C)   one   C D, one   C d, one   c D, and one   c d gamete.            D)   four   C D gametes.            E)   four   c d gametes

Put the following events concerning homologous recombination (the mechanism by which crossing over occurs) in order. 1 2 3 ين 4 Strand invasion and formation of the D-loop Resolution of holiday junctions Initiation of a double stranded break of one non-sister chromatid. Remove nucleotides from ends of DNA strands at the site of the double stranded DNA break.

why The chromatids formedby recombination within the inversion loop of a paracentric inversionheterozygote   containtwo centromeres or none, instead of the normal one ?

why The chromatids formed byrecombination within the inversion loop of a pericentric inversionheterozygote are genetically unbalanced?

Explain two ways that a chromosomal rearrangement can cause a position effect.

Explain why recombination events do not always result in crossing-over.