Top6-Ch7-P161-167

Question 1

Male pattern baldness is influenced by

Answer 1

a variety in the androgen receptor

Question 2

Male pattern baldness is linked to markers on the __-chromosome

Answer 2

X

Question 3

Bald males are more likely to suffer from

Answer 3

heart disease, high blood pressure and prostate cancer

Question 4

Scientists found that some pairs of genes (did/did not) separate according to Mendel’s principles. What is correct did or did not?

Answer 4

did not

Question 5

Principle of segregation is?

Answer 5

each individual diploid organism possesses two alleles at a locus that separate in meiosis with one allele going into each gamete.

Question 6

Principle of independent assortment is?

Answer 6

it provides additional information about the process of segregation; it tells us that, in the process of separation, the two alleles at a locus act independently of alleles at other loci.

Question 7

What are linked genes?

Answer 7

Genes that are located close together on the same chromosome. The linked genes belong to the same linkage group.

Linked genes travel together in meiosis, eventually arriving at the same destination (the same gamete) and are not expected to assort independently.

Closely linked genes are rarely reshuffled.

It was proposed in the early 1900s by Sturtevant that the degree of linkage may depend on the position of the genes on the chromosome. Sturtevant produced the first chromosome map of the X-chromosome of Drosophila melanogaster

Linked genes will give variations on the 9:3:3:1 ratio expected from an independent dihybrid cross

Question 8

Genes located on the same chromosome ___ ___ adhere strictly to Mendel’s principles

Answer 8

do not

Question 9

Recombination is?

Answer 9

the independent separation of alleles, or the sorting of alleles into new combinations.

Question 10

Gametes produce in F1 that are different from parent gametes are

Answer 10

recombinant gametes

Question 11

What is the chromosome theory of heredity and who came up with it and when?

Answer 11

Walter Sutton in 1903. Theory states that genes are found on chromosomes, or chromosomes are the carriers of genetic material and showed that chromosomes separate during meiosis

Question 12

Genes close together on the same chromosome usually segregate as a unit and are therefore inherited ______

Answer 12

together

Question 13

1. Genes located on the same chromosome will sometimes _____ ______
2. The further the genes are _____ the more often crossing over will take place between them
3. Ultimately, they will be inherited as non-linked genes as long as they are far enough _____ on the same chromosome

Answer 13

1. cross over
2. apart
3. apart

Question 14

If genes are completely linked no ______ _______ occurs, but in realilty genes are ____ completely linked.

Answer 14

crossing over, rarely

Question 15

If genes are unlinked then they assort _____

Answer 15

independently.

Question 16

The following diagram shows the difference between completely linked genes and independently assorting genes

Answer 16

Question 17

What are nonrecombinant gametes?

Answer 17

or parental gametes are gametes that contain only original combinations of alleles that are present in the parents.

Question 18

What are nonrecombinant progeny?

Answer 18

Progeny that display the orginal combination of traits present in the P generation or parental progeny

Question 19

Recombinant gametes are?

Answer 19

gametes with new combinations of alleles. Crossing over produces recombinant gametes. Linkage is rarely complete

Question 20

Recombinant progeny are ?

Answer 20

progeny with new combinations of traits formed from recombinant gametes.

Question 21

1. When genes are linked and some crossing over takes place, ________ progeny dominates
2. Recombination frequency can be ______
3. Linkage is a measure for the _____ between two genes on a chromosome
4. Linkage also depends on ______ and _____

Answer 21

1. non-recombinant
2. calculated
3. distance
4. coupling and repulsion