Tom is an expactant father who is worried that he will pass on his Haemophilia A, an X linked recessive disease, to his offspring. The mother is homozygous dominant. Explain why his 1st generation offspring will not be affected by the condition.

A recessive inheritance pattern means that 2 copies of the mutant allele need to be inherited for the individual to be affected. The disease is X linked, meaning the allele is only found on the X chromosome. So a male only needs one copy of this allele to be affected.If Tom's offspring is male then he won't be affected as he would have inherited the Y chromosome from his father, not the X chromosome so he isn't even a carrier.If Tom's offspring is female then she also won't be affected becuase she only has one copy of this allele, so she is just a carrier.

Answered by Eilidh W. Biology tutor

1521 Views

See similar Biology A Level tutors

Related Biology A Level answers

All answers ▸

Explain the role of auxins in the control of phototropism


What affects enzyme activity?


Describe the differences between the primary and secondary immune responses in terms of B cells and antibody production. Include in your answer a definition of an antibody.


During the light-independent reaction of photosynthesis, carbon dioxide is converted into organic substances. Describe how. (6marks)


We're here to help

contact us iconContact usWhatsapp logoMessage us on Whatsapptelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo
Cookie Preferences