Question

Activity 8

Albinism in humans is controlled by a recessive gene (c). Suppose two heterozygous individuals (genotype Cc) marry. Assume they have six children.

A. What is the probability that at least one child will be albino?

B. What is the probability that three will be albino and three will have pigmentation?

C. A challenge: What is the probability that three of the children will be boys AND all three boys will be albino? Hint assume gender is independent of whether or not a child turns out to be albino. Not too tricky if you think carefully!

Activity 9

Flip 5 coins 128 times.You can use actual coins or use. You should have 6 expected classes. Get your expected ratio from Pascal'striangle

http://shazam.econ.ubc.ca/flip/

Keep a tally sheet. Do a chi square. Do your data fit expections?

Answer 1

Albinism in humans is controlled by a recessive gene (c). Suppose two heterozygous individuals (genotype Cc) marry. Assume they have six children.............

Cc x Cc

gametes are C, c

	C	c
C	CC (normal)	Cc(normal)
c	Cc (normal)	cc (albinism)

75% are normal and 25% show albinism

out of the 6 offsprings, how many show albinism................

A. What is the probability that at least one child will be albino?

75 x 75 x 75 x 75 x 75 x 75 = 0.17

one mightt show albinism

So,   1- 0.17 = 0.83

The probability one child must be albino is 83%

B. What is the probability that three will be albino and three will have pigmentation?

75 x 75 x 75 x 25 x 25 x 25 = 0.0065

However there are 20 different ways for three children to be albino.........20 x 0.0065 = 0.131 or 0.132

Tthree will be albino and three will have pigmentation have a probability of 13.2%

C. A challenge: What is the probability that three of the children will be boys AND all three boys will be albino? Hint assume gender is independent of whether or not a child turns out to be albino. Not too tricky if you think carefully!

If we assume 50% of being a boy and 50% being a girl out of total children

0.50 x 0.50 x 0.50 x 0.50 x 0.50 x 0.50 x 20 = 0.3125 = 31.25 %

Three children shows albinism = 0.25 x 0.25 x 0.25 = 0.015

now multiply ............0.3125 x 0.015 = 0.0046 or nearly 5% are boys and all the three are albino.