Achondroplasia, which is characterized by difficulty converting cartilage to bone and thus results in shortened limbs. This trait is autosomal dominant. (A = achondroplasia allele; a = average height allele.) A husband and wife both have achondroplasia. The couple have a total 12 living children: 6 boys and 6 girls.  The husband is colorblind, which is an X-linked recessive trait, and the wife believes there is a chance she is a carrier of colorblindness, since that trait runs in her family. One of the couple’s daughters and three of their sons are colorblind.  (Xc = colorblindness allele; XC = normal color vision allele.) a) Draw a Punnett square that illustrates the GENOTYPES of all of the children that could be CONCEIVED by this couple.  b) What fraction of all of this couple's LIVING/SURVIVING children will have achondroplasia AND simultaneously be colorblind?

The pedigree below represents the inheritance of a rare genetic disorder (members joining the pedigree are not carriers). Consider the following pedigree and answer questions (i) to (vii) below. The allele descriptors are B/b. What is the mode of inheritance in this pedigree ? Y-linked inheritance X-linked recessive inheritance X-linked dominant inheritance Autosomal recessive inheritance Autosomal dominant inheritance   What is the genotype of individual III-2 ? a) XbXb b) XBXB c) XBXb d) Bb e) bb   What is the genotype of individual IV-3 ? a) XbXb b) XBXB c) XBXb d) Bb e) bb   Individual IV-4 and an unaffected woman is planning a family. What is the probability that their first child will be phenotypically normal ? a) chance that the first child will be phenotypically normal. b) chance that the first child will be phenotypically normal. c) chance that the first female child will be phenotypically normal; all male children will be phenotypically normal. d)  chance that the…

A couple who is heterozygous for simple recessive albinism (no epistasis here) plans on having 2 kids. What is the probability their children will have the same phenotype?

YOUR SISTER DIED FROM TAY-SACHS DISEASE, INHERITED AS A RECESSIVE ALLELE (t). you're married and planning to start your family. you're worried about the disease and decide to have genetic testing to see if you or your spouse is a carrier of the tay-sachs allele. the test results show that you're a carrier of the allele, but your spouse isn't. what is the probability that you and your spouse will have a child with tay-sachs disease? show your work.