× Didn't find what you were looking for? Ask a question
Top Posters
Since Sunday
g
2
New Topic  
Biologylover200 Biologylover200
wrote...
Posts: 1
Rep: 0 0
8 years ago
A man with hemophilia (a recessive, sex-linked condition) has a daughter of normal phenotype. She marries a man who is normal for the trait. What is the probability that a daughter of this mating will have hemophilia? That a son will have hemo- philia? If the couple has four sons, what is the probability that all four will be born with hemophilia?
Read 488 times
1 Reply

Related Topics

Replies
wrote...
8 years ago
The man is X*Y where his X-chromosome carries the mutation. He shows the phenotype as he has no back-up good copy of the affected gene.

His daughter inherits the affected X-chromosome from her father and I assume a normal X-chromosome from her mother so she X*X. Since she has a back up good copy of the gene on her unaffected X-chromosome she is phenotypically normal.

She marries a man who is normal, XY.

Any daughters produced from this mating will have at least one normal X (from the father) so will be phenotypically normal i.e. 0% chance of having haemophillia.

Any sons produced from this mating have a 50% chance of inheriting the affected X-chromosome from the mother i.e. 50% chance of haemophillia for any son.

For all 4 sons: (50%)^4 = 6.25%
New Topic      
Explore
Post your homework questions and get free online help from our incredible volunteers
  1249 People Browsing
Show Emoticons
:):(;):P:D:|:O:?:nerd:8o:glasses::-):-(:-*O:-D>:-D:o):idea::important::help::error::warning::favorite:
Related Images
  
 264
  
 356
  
 4243
Your Opinion
What percentage of nature vs. nurture dictates human intelligence?
Votes: 452

Previous poll results: How often do you eat-out per week?