15.2

Question 1

Who predicted that the distance between genes can be used as recombination data?

Answer 1

Alfred Sturtevant

Question 2

Distances between genes can be expressed as …?

Answer 2

Map units

Question 3

Map units represent what percent of recombination frequency?

Answer 3

1%

Question 4

What do map units indicate?

Answer 4

Relative distance and order, not precise locations of genes

Question 5

Genetically unlinked

Answer 5

Behave as if found on different chromosomes

Question 6

Sturtevant used ______ _____ to make linkage maps of fruit fly genes.

Answer 6

Recombination frequencies

Question 7

Linkage groups

Answer 7

Genes clustered into four groups

Question 8

Linkage maps proved that there are 4 chromosomes in Drosophila and provided additional evidence that …?

Answer 8

Genes are located on chromosomes

Question 9

Alterations of ___ ____ or structure cause some genetic disorders

Answer 9

Chromosome number

Question 10

Miscarriages

Answer 10

Large-scale chromosomal alterations in humans and other mammals often lead to spontaneous abortions

Question 11

Nondisjunction

Answer 11

Pairs of homologous chromosomes that do not separate normally during Meiosis

Question 12

What happens to the gametes in nondisjunction?

Answer 12

One gamete receives 2 of the same chromosome and the other receives no copy

Question 13

When does nondisjunction take place?

Answer 13

Anaphase

Question 14

Aneuploidy

Answer 14

Fertilization after nondisjunction occured

Question 15

Monosomic

Answer 15

Zygote has only one copy of a particular chromosome

Question 16

Trisomic

Answer 16

Zygote has three copies of a particular chromosome