BackA couple comes into your genetic counseling practice with a question about the chance a future child of theirs might have a genetic disease. Three or four men in the woman's family, including her father, had a condition that might be genetic. Although her father is still alive, she has had little contact with him for much of her life and cannot describe or name the condition. Her partner is a healthy man whose family has no history indicating the presence of a genetic condition. To provide more information about this possible genetic condition for the couple, what is the first step you recommend?
In mice, black coat color is dominant to white coat color. In the pedigree shown here, mice with a black coat are represented by darkened symbols, and those with white coats are shown as open symbols. Using allele symbols B and b, determine the genotypes for each mouse.
Nail–patella syndrome is an autosomal disorder affecting the shape of nails on fingers and toes as well as the structure of kneecaps. The pedigree below shows the transmission of nail–patella syndrome in a family along with ABO blood type.
Explain why III-6 has nail–patella syndrome and III-8 does not. Give genotypes for these two individuals.
Nail–patella syndrome is an autosomal disorder affecting the shape of nails on fingers and toes as well as the structure of kneecaps. The pedigree below shows the transmission of nail–patella syndrome in a family along with ABO blood type.
Using N and n to represent alleles at the nail–patella locus and Iᴬ, Iᴮ and i to represent ABO alleles, write the genotypes of I-1 and I-2 as well as their five children in generation II.
Consider this human pedigree for a vision defect.
What is the most probable mode of inheritance of the disease? Identify any discrepancies between the pedigree and your proposed mode of transmission, and provide possible explanations for these exceptions.
The accompanying pedigree shows the transmission of albinism (absence of skin pigment) in a human family.
One child of female I-3 has albinism. What is the probability that any of the other four children are carriers of the allele for albinism?
The accompanying pedigree shows the transmission of albinism (absence of skin pigment) in a human family.
What is the probability that female I-3 is a heterozygous carrier of the allele for albinism?
The accompanying pedigree shows the transmission of albinism (absence of skin pigment) in a human family.
Using allelic symbols of your choice, identify the genotypes of the male and his two mates in generation I.
The accompanying pedigree shows the transmission of albinism (absence of skin pigment) in a human family.
What is the most likely mode of transmission of albinism in this family?