Complex Inheritance
Sex-Linked
VI. Sex-linked Inheritance
Traits inherited on the X or Y chromosome are
said to be sex-linked because inheritance
differs depending on the sex of the person.
A. How sex is Inherited
O Females (♀) always give an X chromosome.
O Males (♂) give either an X or a Y.
O There is always a 50/50 chance of male or
female.
B. X-Linked Inheritance
O ♀’s carry 2 alleles on
X.
O ♂’s only carry one
allele on X.
C. Explanation
O Sex-linked Inheritance- Amoeba Sisters
O https://www.youtube.com/watch?v=h2xufrH
WG3E
D. Example: Colorblindness
C= “normal” vision
c = colorblind
XC XC = “Normal”
XC Xc = “Normal”
Xc Xc = colorblind
XC Y = “Normal”
Xc Y = colorblind
XC XC = “Normal”
XC Xc = “Normal”
Xc Xc = colorblind
XC Y = “Normal”
Xc Y = colorblind
O Mom carries colorblind gene, dad has
normal vision:
XC Xc x Xc Y
XC
Xc
XC
XC XC
XCXc
Y
XC Y
XcY
2 normal ♀
1 normal ♂
1 colorblind ♂
Colorblind Test
O https://www.youtube.com/watch?v=E8kj_y9
Zic0
E. Hemophilia
O An X-linked trait, when in the homozygous form
does not allow the proper clotting of blood.
O See Hemophilia Lab and Video link below.
O https://www.youtube.com/watch?v=bmQwMllhC
UM