PATHOLOGY

PATHOLOGY MCQ

GENETICS AND DISEASE

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
Colorblindness is a recessive x-linked disorder. Which genotype represents a male with normal vision?
A
XNXN
B
XnXn
C
XNY
D
XnY
Explanation: 

Detailed explanation-1: -Let (Xc) represent the recessive allele that causes colorblindness and (X+) represent the normal dominant allele. Females that are X+X+ or X+Xc have normal color vision, while XcXc females are colorblind. Males that are X+Y have normal color vision, while XcY males are colorblind.

Detailed explanation-2: -Males have 1 X chromosome and 1 Y chromosome, and females have 2 X chromosomes. The genes that can give you red-green color blindness are passed down on the X chromosome. Since it’s passed down on the X chromosome, red-green color blindness is more common in men.

Detailed explanation-3: -Examples of X-linked recessive conditions include red-green color blindness and hemophilia A: Red-green color blindness. Red-green color blindness means that a person cannot see shades of red and green (usually blue-green).

Detailed explanation-4: -Examples of X-linked recessive conditions include red-green color blindness and hemophilia A: Red-green color blindness. Red-green color blindness means that a person cannot distinguish shades of red and green (usually blue-green), but their ability to see is normal.

There is 1 question to complete.