Sex Linked GeneS

Question 1

Autosomes vs sex chromosoms

Answer 1

Humans have 22 pairs of autosomal and one pair of sex determining chromosomes

Question 2

Females vs. Malses

Answer 2

Femlas have homologous x chromosomes
Males have xy
Even if nondysjunction occurs, as long as there is a y chromosome the person will be male
- xxx = female
-xxy = male
- x = female (only case of survival for monosomy)
- y = dead (not enough genetic info for survival)

Question 3

X linked traits

Answer 3

Because males only have 1 x chromosome, even if they have a recessive gene on their x chromosome jt will be expressed (there’s no second chromosome to mask the recessive gene)

Because girls have 2 x chromosomes they still need two pairs of recessive Gene’s to be expressed

Question 4

Y linked traits

Answer 4

All sons of affected fathers will have jt

Question 5

Inheritance of x linked gene disorders/traits

Answer 5

Males:
Xy - normal
Xhy - affected

Female:
Xx - normals
Xhx - carrier
Xhxh - affected

Question 6

Klinefelter syndrome

Answer 6

Extra x
= xxy
- common, 1 in 500 men
- secondary sex characteristics fail to develop
- most are infertile

Question 7

Turner syndrome

Answer 7

Only one x

• females
• short stature, webbed neck, non menstruation, undeveloped ovaries, no breaststroke
• increased risk of heart disease and diabetes