Top Posters
Since Sunday
a
5
k
5
c
5
B
5
l
5
C
4
s
4
a
4
t
4
i
4
r
4
r
4
Home Q & A Board Biology-Related Homework Help Genetics and Developmental Biology
New Topic  
sandmanfan01 sandmanfan01
wrote...
Go to Answer
Posts: 2
Rep: 1 0
9 years ago Edited: 9 years ago, sandmanfan01
An alternative to using the expanded binomial equation and Pascal's triangle in determining probabilities of phenotypes in a subsequent generation when the parents' genotypes are known is to use the following equation:

(n!/s!t!) (a^s*b^t)

where n is the number of offspring, s is the number of offspring in one phenotypic category, t is the number of offspring in the second phenotypic category, a is the probability of the occurance of the first phenotype, and b is the probability of the occurance of the second phenotype. Using this equation, determine the probability of a family of 10 offspring having exactly 2 children afflicted with sickle cell anemia (an autosomal recessive disorder) when both parents are heterozygous for the sickle-cell allele.

I don't know how to answer this.
Read 2734 times
4 Replies
Replies
wrote...
#1
Staff Member
Educator
9 years ago
n = 10

s = 3

t = 7

a = .25 (A mendelian cross of two heterozygous parents will produce the genotypes SS, Ss, Ss, and ss. Because only autosomal recessive individuals (ss) are affected by the disease, one-fourth (0.25) children are afflicted with sickle cell anemia.)

b = 1 - .25 = .75



P = (10! / (3! X 7!)) (.25^3)(.75 ^ 7)

P = 0.25
Mastering in Nutritional Biology
Tralalalala Slight Smile
Answer accepted by topic starter
sandmanfan01 Authorsandmanfan01
wrote...
#2
Posts: 2
Rep: 1 0
9 years ago Edited: 9 years ago, sandmanfan01
Sign in or Sign up in seconds to unlock everything for free

Related Topics

wrote...
#3
Staff Member
Educator
9 years ago
Thanks for the update
Mastering in Nutritional Biology
Tralalalala Slight Smile
wrote...
#4
3 years ago
thank you
New Topic      
Quick Reply
Explore
Post your homework questions and get free online help from our incredible volunteers
  1231 People Browsing
 127 Signed Up Today
Start New Topic Take the Tour CoursesNew Study Tools Topics Trending Browse by Textbook
Related Images
  
 3406
  
 83
  
 183
Your Opinion
Who's your favorite biologist?
Votes: 586
Previous poll results: Do you trust social media networks with protecting your privacy?