2 Homework Page 1 BIOL 360 Genetics BIOL 360 Spring 2017 Mar

2 Homework Page 1 BIOL 360 Genetics: BIOL 360 Spring 2017 Marian Coffie #16 instructions help Cystic fibrosis is an autosomal recessive disorder that affects lung function humans. A man and a woman are both unaffected heterozygous in what is th probability that their first child unaffected and their carriers of a cystic fibrosis gene. the couple has two children, will be second child will be unaffected? rev om 21.2015 oc cs 4444.02 o 2015 QC cs 6269 O 6.25% O 18.75% O 56.25% References eBooks & Resources Section 205 C2017 MoGrew HIl Education. All rights reserved.

Solution

*** I am answering the first question. Please post other parts separately.

Cystic fibrosis is autosomal recessive. Let us take the symbol for normal gene to be \'C\'.

Parents are heterozygous.

So, cross will be Cc X Cc

Chances of having the first as well as second child to be affected with cystic fibrosis = 1/4 = 0.25

Chances of having unaffected child = 3/4 = 0.75 =number of favorable outcomes is 3. This is in Mendelian fashion i.e. 3:1.

Probability of having unaffected child = number of favorable outcomes/total number of possible outcomes

= 3/4 = 0.75 is the probability of having an unaffected child. Please note that your options are incorrect.