Recitation 6 short-answer assignment Cystic fibrosis is an autosomal recessive d
ID: 141632 • Letter: R
Question
Recitation 6 short-answer assignment Cystic fibrosis is an autosomal recessive disorder caused by a loss-of-function mutation in a chlorine channel, which causes a thickening of the mucus, leading to respiratory failure. This disease affects approximately 1 in 1353 newborns in the Republic of Ireland every year. Fill in the following values (1 points each): p 0.027 q0.972 Current population of Ireland is approximately 4.8 million. Based on the allele frequencies that you calculated, what is the expected number of cystic fibrosis carriers (heterozygotes) in Ireland? Show your work. (1 point) Population: 4.8 million Frequency of heterozygous 2pq 0.052488 No. of carriers population size x frequeny 4.8 x10 6 x0.052488 251,942.2 0.25 million What is the expected number of healthy individuals in the population? Show your work.(1 point Reminder: only homozygous recessive individuals are affected by the disease Expected healthy p2+2pq 1 q42-0.999Explanation / Answer
Q.1
1353/4,800,000 = 0.000281875 * 100 = 0.0281875
q = 0.0281875 (recessive allele)
p + q = 1
1 - 0.0281875 = 0.9718125
p = 0.9718125 (dominant allele)
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Q.2
P2 + 2pq + q2 = 1
Heterozygous (Carrier) = 2pq
= 2 * 0.9718125 * 0.0281875
= 0.0547859296875
# of heterozygous carrier = freq. * population size
= 0.0547859296875 * 4,800,000
= 262,972.4625
= 0.262972 million
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Q.3
Homozygous Dominant (Unaffected) + Heterozygous (Carrier) = p2 + 2pq
= 0.94441953515625 + 0.0547859296875
= 0.99920546484375 * 4,800,000
= 4,796,186.23125
= 4.796186 million
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Q.4
CC, expected # = p2 * 100,000
= 0.94441953515625 * 100,000
= 94,441.953515625
Cc, expected # = 2pq * 100,000
= 0.0547859296875 * 100,000
= 5,478.59296875
cc, expected # = q2 * 100,000
= 0.00079453515625 * 100,000
= 79.453515625
Total,
CC + Cc + cc = 100,000
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cc, observed # = 65
q2 = 65/100000 = 0.00065
q = 0.02549509756796392415014112054511
p + q = 1
p = 1 - 0.02549509756796392415014112054511
= 0.97450490243203607584985887945489
p2 = 0.94965980486407215169971775890978
2pq = 2 * 0.97450490243203607584985887945489 * 0.02549509756796392415014112054511
= 0.04969019513592784830028224109022
CC, observed # = 0.94965980486407215169971775890978 * 100000
= 9,4965.980486407215169971775890978
Cc, observed # = 0.04969019513592784830028224109022 * 100000
= 4,969.019513592784830028224109022
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(Observed - Expected)2 / Expected
CC = (9,4965.980486407215169971775890978 - 94,441.953515625 )2 / 94,441.953515625
= 2.9076512702773830311596198993132
Cc = (4,969.019513592784830028224109022 - 5,478.59296875)2 / 5,478.59296875
= 47.396312827398778402189872699143
cc = (65 - 79.453515625)2 / 79.453515625
= 2.6292620569251134458532652248514
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