Linkage, Recombination, & Eukaryotic Gene Mapping

Question 1

Linked

Answer 1

When genes are close together on the same chromosome. Meaning the alleles, or gene versions, already together on one chromosome will be inherited as a unit more times than not.

Question 2

Unlinked Genes

Answer 2

When genes are found on different chromosomes or far apart on the same chromosome, they assort independently.

Question 2

Nonrecombinant gametes

Answer 2

Gamete that contains only the original combinations of alleles that were present in the parents

Question 3

Recombinant gametes

Answer 3

Lower frequency

Question 4

Homologous Recombination

Answer 4

Occurs during:

Prophase I of meiosis

A tetrad or bivalent (this means 4 homologous chromatids) is formed

A chiasma (this is the physical junction between the homologous chromatids) is the site where recombination occurs

Question 5

No crossing over steps

Answer 5

1. Homologous chromosomes pair in prophase I
2. Each gamete receives a nonrecombinant chromosome with an original combination of alleles

Question 6

Crossing over steps

Answer 6

1. A crossover may take place in prophase I

Meiosis II –>

2. In this case, half of the resulting gametes will have an unchanged chromosome (parental/nonrecombinant)
3. And half will have recombinant chromosomes