Use a genetic diagram to work out the probability that the offspring have cystic fibrosis if both parents are carriers.

CF is a homozygous recessive condition. This means that it is inherited, ie a child gets the condition by the genetic material passed on to it from its parents. Let's call the faulty allele f (which is also the recessive allele) and let's call the non-faulty allele F (which is also the dominant allele). 
If both parents are carriers this means they have the genotype Ff. Being a carrier remember means that you still have one faulty allele but you do not present with symptoms as you do not have the disease because in order to be affected you must have 2 faulty alleles.
(In my lesson I would then draw out the genetic diagram to explain how the ratios can be calculated.)

Answered by Eksha G. Biology tutor

2554 Views

See similar Biology GCSE tutors

Related Biology GCSE answers

All answers ▸

What are the main methods the human body uses to prevent infection from micro-organisms?


Describe how the hormones FSH, oestrogen and LH are involved in the control of the menstrual cycle


what is mitosis


b)Plants can use the glucose they have made to supply them with energy. Give four other ways in which plants use the glucose they have made.


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