Chapter 15

Question 1

Wild type

Answer 1

Refers to the phenotype most commonly observed in natural populations

Question 2

What did Morgan observe with his fruit fly crosses that led him to conclude that eye color in Drosophila is an X-linked trait?

Answer 2

The gene for eye color is on the X chromosome

Question 3

X linked recessive traits

Answer 3

•Males have only one copy of X linked genes; males are hemizygous
-males display the phenotype specified by the single X chromosome
•females may be heterozygous and carry X linked recessive mutations
-X linked recessive is seen more in males

Question 4

Dosage compensation

Answer 4

The equalization of gene expression between the males and females of species

Question 5

X inactivation in female mammals

Answer 5

In female somatic cells equalizes the effective dosage of X linked genes

Question 6

Barr body

Answer 6

Inactivated chromosome is highly condensed

Question 7

Sex determination

Answer 7

X-Y
X-O
Z-W
Haploid-diploid system

Question 8

X-Y

Answer 8

Determined by whether the sperm has an X chromosome or a Y chromosome

Question 9

X-O

Answer 9

Determined by whether the sperm has an X chromosome or no sex chromosome

Question 10

Z-W

Answer 10

Determined by whether the egg has a Z or a W Chromsome

Question 11

Haploid-diploid system

Answer 11

Females develop from fertlized eggs, males from unfertilized eggs

Question 12

X-linked genes are?

Answer 12

Genes located on the x-chromosomes