Phenylketonuria, a Metabolic disease in humans, is caused by a recessive allele, k. If two heterozygotes marry and plan a family of six children: a)what is the probability that all will be unaffected? b)what is the probability that three will be unaffected and three will be affected? c)what is the probability that at least two will be unaffected? d)what is the probability that the first child will be an unaffected girl?
I don't even know how to approach this problem. Much help is needed. Thanks

  1. 👍 1
  2. 👎 0
  3. 👁 872
  1. Prob each is affected= 1/2*1/2= 1/4

    prob all unaffected= (3/4)^6

    prob three affected= (1/4)^3 * (3/4)^3 * ways.

    now ways = 6!/3!3!

    at least two will be unaffected
    combination ways
    uuaaaa 6!/(2!4!)= 15
    uuuaaa 6!/(3!3!)=40
    uuuuaa 6!/(2!4!) =15
    uuuuua 6!/5!1! =6
    uuuuuu 6!/6! =1

    check those, I did them in my head
    Pr(at least two)= sum prob*combinations
    = 15((3/4)^2(1/4)^4)+40((3/4)^3(1/4)^3)+ ....

    pr first child ug?
    Pr= (3/4)*1/2

  2. I don't get b or c at alll. What are the u's and a's? What are the exclamation points?

    1. 👍 0
    2. 👎 0

Respond to this Question

First Name

Your Response

Similar Questions

  1. Science

    What does the notation TT mean to geneticists? A. Two dominant alleles B. Heterozygous C. At least one dominant allele D. One dominant and one recessive allele Is the answer A?

    asked by Anonymous on October 10, 2014
  2. science

    1) a pea plant with yellow seeds is crossed with a pea plant with green seeds. all of the offsprings have yellow seeds. the allele for yellow sees is a. Dominate because all offspring have yellow seeds. b. Recessive because all of

    asked by dani on October 21, 2014
  3. Science

    1. Which of the following traits is acquired A. the number of petals that grow in a plant's flowers B. the wing shape of a wild bird C. the ability of some gorillas to use sign language D. a cheetah's ability to run faster than

    asked by homework help on December 13, 2013
  4. Science

    1. White skin (W) is dominant over yellow skin (w) in chickens. Which of the following genotypes would result in a white-skinned chicken that could possibly have yellow-skinned offspring? A. WW B. Ww** C. ww 2. Which of the

    asked by Mimmi on October 7, 2015
  5. genetics

    1. Long wings (L) in fruit flies is dominant to short wings (l). If you had a fruit fly with long wings, what mating would you set up to test if it was LL or Ll genotype? 2. Jane's mother died of Huntington's disease (a dominant

    asked by emir on April 22, 2014
  1. science Help

    Which of the following describes the genotype and phenotype of parents whose child will definitely have a recessive trait? A. Both parents are homozygous for the recessive allele and have the trait. B. Both parents are homozygous

    asked by Gwen on September 23, 2014
  2. Science

    Hemophilia is an inherited bleeding disorder where the blood does not clot properly. This disorder is caused by a recessive allele on the X chromosome, a couple just learned that their daughter has hemophilia. They already have a

    asked by Kenzie on November 16, 2019
  3. biology

    Consider the pedigree below. This pedigree represents a family with a rare genetic disease. Note two very important assumptions: Individuals who marry into the family may carry a disease allele. The disease is completelely

    asked by selly on April 7, 2013
  4. science

    About 70% of the human population can taste the bitter chemical phenylthiocarbamide (PTC), which is found in foods like broccoli. The allele, T, for tasting PTC is dominant over the allele, t, for not tasting it. Calculate the

    asked by madison on November 10, 2012
  5. Genetics

    In chickens, the Leghorn variety has white feathers due to an autosomal dominant allele. Silkies have white feathers due to recessive allele in a second gene. If true-breeding white leghorn is crossed to a true breeding white

    asked by Iris on October 10, 2012
  6. science PLZZZ HELP

    The pedigree above shows the family history of the recessive blood disorder sickle-cell anemia. What are the chances of the child I having the disease or carrying the gene for the disease? A. Child I has no chance of having the

    asked by Anonymous on February 1, 2019

You can view more similar questions or ask a new question.