Ichthyosis is a rare X-linked recessive disorder that is characterized by scaling of the skin around the neck and lower extremities. A young couple, Bart and Jenny, are expecting a child and are aware there might be a chance that their child could be affected by this disorder. Jenny (the wife) has ichthyosis, but Bart (her husband) is unaffected and completely normal with respect to the allele responsible for this disorder. A. Both Bart and Jenny were Biology majors as undergraduates. Knowing a little about the pattern of X-linked recessive inheritance, Bart and Jenny were concerned when ultrasound revealed that they would be having a son. However, genetic testing performed on the baby shortly after birth revealed that their newborn son, Mark, did not have ichthyosis. Explain how this could be the case, assuming that the gene responsible for ichthyosis is fully penetrant. If non-disjunction occurred, assume it happened in only one of the two parents, and during only one of the two meiotic divisions. PLEASE BE SPECIFIC. B. Name and define the syndrome associated with the aneuploidy of the sex chromosomes that is present in baby Mark. Be sure to mention the specific sex chromosomes Mark possesses, and name two major phenotypic characteristics associated with this disorder. C. Define the alleles associated with X-linked recessive ichthyosis, using the type of genetic notation utilized for disorders showing a similar pattern of inheritance. (eg. S^L and S^S) (i) Ichthyosis allele: (ii) Normal allele:
Ichthyosis is a rare X-linked recessive disorder that is characterized by scaling of the skin around the neck and lower extremities. A young couple, Bart and Jenny, are expecting a child and are aware there might be a chance that their child could be affected by this disorder. Jenny (the wife) has ichthyosis, but Bart (her husband) is unaffected and completely normal with respect to the allele responsible for this disorder.
A. Both Bart and Jenny were Biology majors as undergraduates. Knowing a little about the pattern of X-linked recessive inheritance, Bart and Jenny were concerned when ultrasound revealed that they would be having a son. However, genetic testing performed on the baby shortly after birth revealed that their newborn son, Mark, did not have ichthyosis. Explain how this could be the case, assuming that the gene responsible for ichthyosis is fully penetrant. If non-disjunction occurred, assume it happened in only one of the two parents, and during only one of the two meiotic divisions. PLEASE BE SPECIFIC.
B. Name and define the syndrome associated with the aneuploidy of the sex chromosomes that is present in baby Mark. Be sure to mention the specific sex chromosomes Mark possesses, and name two major
C. Define the alleles associated with X-linked recessive ichthyosis, using the type of genetic notation utilized for disorders showing a similar pattern of inheritance. (eg. S^L and S^S)
(i) Ichthyosis allele: (ii) Normal allele:
Step by step
Solved in 4 steps
