A genetics counselor, Nashaly Montez, notices an odd pattern in Devin’s pedigree, a propensity for cancer development in his family at a higher incidence in males compared to females. This suggests to Nashaly an X-linked recessive disorder that is not manifesting in females as frequently compared to males who only have one X chromosome. She brings this to the attention of Devin’s primary health care provider who has his client checked for common cancer-causing mutations. A mutant LOF Fox3 regulatory allele is found that has an early NONSENSE codon that prevents protein expression. This is unfortunate, since in its wildtype form the protein is normally tumor-suppressing. 1) Nashaly, the genetics counselor, is doing academic research on Fox 3 gene expression in a genetically engineered bacterial strain transfected with recombinant DNA. By exposing the bacterium to increased heat, she induces a mutation in the ribosome and not the gene. Transcripts can bind to the mutant ribosome but translation soon halts and the uncharged stem of tRNA for initiator methionine never exits the ribosome. Where is the mutation in the ribosome? a Perhaps the A channel’s shape has been altered so the next amino acid can never be delivered, which halts translation. b Perhaps something is blocking the E channel so the uncharged tRNA methionine initiator stem is never allowed to leave, which halts translation. c Perhaps the peptidyl center of the ribosome is damaged and no longer functions to hook on the next amino acid, which halts translation. d All the answers could be correct.

Mrs. and Mr. Bond have five children, Janine, Jaliyah, Joliette, Jelani and James Jr. Mr. Bond suffers from fragile X syndrome, an X-linked disease (i.e., on chromosome X) which is also dominant. Mrs. Bond is healthy. Janine, Jaliyah, Joliette and Jelani have fragile X syndrome, while James Jr. is healthy. Is there reason to suspect infidelity in this family?

Colorblindness is an X-linked trait found in humans. What are the chances that a colorblind man will pass it on to his son? Please explain.

Divya is 32 years old. She has found a small lump in her left breast and decided to go to her GP for a check-up. Her GP examined her and asked whether terse was any family history of cancer. She said her sister had breast cancer and he mother had died of ovarian cancer. Divya said there were also cases of cancer within her extended family. The pedigree below shows 3 generations of Divya’s family. The GP analysed the pedigree and concluded there was likely to be an inherited mutation running through Divya’s family and immediately referred her for a mammogram and a biopsy of the lump. Tissue from the biopsy was set for gene testing. Part 1 What type of inherited cancer syndrome appears to be present in Divya’s family? Part 2 What is the name of the gene being tested for matrons and what gene class does it belong to? Part 3 Are inherited mutations in this gene loss of function, gain of function or silent? Would you expect an individual to inherit a mutation in both parental copies of this…

A defective gene on chromosome 15 causes Tay-Sachs disease. It is a central nervous system neurodegenerative disease that most often affects infants, though older children and adults can have late-onset forms of the disease. The defective gene prevents the body from making a protein called hexosaminidase A. Without, hexosaminidase A, chemicals called gangliosides build up in the nerve cells of the brain, destroying brain cells. Pedigree information regarding the incidence of Tay-Sachs within a family is depicted above. The row below that indicates the genotypes of individuals II-1, II-2, and III-1 is Select one: a. II-1 II-2 III-1 Aa Aa aa b. II-1 II-2 III-1 XAY XAXa XAXa c. II-1 II-2 III-1 XAY XAXA XaXa d. II-1 II-2 III-1 AA aa Aa

Duchenne’s muscular dystrophy (DMD) is an X-linked disease that causes progressive muscle weakness and is often fatal. “XD” represents the wild type allele, and “Xd,” the mutant allele. Jonah is XDXd Y and his brother Pete is Xd Y. Jonah and Pete BOTH have DMD of equal severity and phenotypes. You might have thought Jonah’s DMD would be less severe given his genotype. To better understand the situation, you investigate Jonah’s Xist chromosome region in his defective muscle cells. Which of the following is consistent with his phenotype? (Select all that apply.) The Xd-containing chromosome is inactive in defective muscle cells. The XD-containing chromosome has a methylated Xist promoter. The XD-containing chromosome has an unmethylated Xist promoter. The Xd-containing chromosome is active in defective muscle cells.

Lauren has chronic bronchitis and frequently ends up hospitalized with pneumonia. She has no family history of cystic fibrosis, a serious recessive genetic disorder which affects respiratory and digestive tracts. She and her husband Nat have one child after undergoing fertility treatments to overcome Nat's infertility. They are surprised when their child is diagnosed with cystic fibrosis and the genetic counselor tells them that they each also have the condition, which causes their bronchitis and infertility. Which of the following would be a reasonable explanation of their situation? Although the underlying disease is genetic, the severity of the disorder if influenced by environmental variation. Cystic fibrosis displays variable expressivity. There are different alleles of cystic fibrosis which cause differing forms of the disease. There are different alleles of cystic fibrosis which cause differing forms of the disease and Cystic fibrosis displays variable expressivity are the only…

The Hulk wants to have children with Black Widow. However, the Hulk is worried that his super genes will pass down to their child. Black Widow is a normal human with a genotype (Nn) and The Hulk has a mutated genotype of (nn). The green gene is recessive. Will their child have super powers?

a) 5% b) 45% c) 90% d) 10%