Draw the pedigree described in the following paragraph, using the Progeny tool. Save your pedigree as a JPEG file and embed it in your Word file. Assume that all family members affected with a metabolic disorder express the trait. For this pedigree, number all members of each generation, even if they have married into the family. As a self-check; if you have drawn the pedigree correctly, the proband will appear as II.6 ; her younger sisters third son will be III.12. Note that inm male-female couples, the male is conventionally placed on the left. A family is attending the genetics clinic. Several members suffer from metabolic disorders; Diabetes mellitis (DM) or impaired glucose tolerance (IGT) or impaired fasting glucose (IFG). IFG and IGT are considered as pre-diabetes and in ~ 70% of cases lead to the full form. The proband has DM and is married. She has three sons, who all have IGT. The eldest is married with one daughter, who is healthy. The proband has two older siblings (a brother and a sister) and a younger sister, who are all married; the first two have diabetes, the younger sister has IGT. The probands brother has a healthy daughter. Her elder sister has two chidren, of either sex, both with IGT. Her younger sister has four sons all with IFG or IGT. They are all married with one healthy daughter each. The probands father is healthy, while the probands mother had diabetes and is deceased. 2. What is the apparent inheritance pattern for this trait? Explain your answer, with reference to the transmission between generations, and the variable symptoms. 3. Name one other trait with the same inheritance pattern, and state the name of the gene locus responsible for this trait. 4. Assume that the locus responsible for the glucose metaboloism character in this pedigree can be occupied by two alternate alleles. Assign symbols to these alleles. Give the genotypes of the proband and her husband. If the pedigree was different, and II.2 expressed the trait and was heterozygous, what would be the phenotype of III.1, and why ? 5. What is the risk that the probands next child will express the trait if it is a boy, or a girl? 6. What is the risk that the next child of II.1 will express the trait, and why ? 7. The daughter of III.12 does not yet show any symptoms. Is this because she is too young? 8. The geneticists extracted leucocyte DNA from cases and controls, and carried out a PCR reaction to amplify regions of several different candidate genes. All the affected family members carried a G->A substitution in the coding region of ND-1, which converted the codon GGG to AGG. Is this a transition or a transversion? Did the amino acid change as a result? Was this substitution conservative or nonconservative? 9. Deamination is a spontaneous mechanism that could have given rise to the mutation described in 8 above. Explain this briefly, and the substitution that would occur in the next round of DNA synthesis. What DNA repair mechanism would need to have failed for this to occur ? A tautomeric mutation mechanism is also possible, as discussed in lecture 3; suggest how this mechanism would produce the G-> A substitution in the next round of DNA synthesis, and why DNA repair would not be engaged in this case. 10. If the mutation had been a gene deletion instead of a point mutation, could this have arisen during meiosis in the mother? Explain your answer. Question 2 . Linkage and positional cloning (32 marks). [A] Pedigree 1 below shows a real family in which several members suffer from degrees of hearing impairment from mild loss in one ear to complete deafness. 1) From the pedigree alone, what is the apparent inheritance pattern for this form of hearing impairment? 2) What is the genotype of the gametes produced by II.1 and II.2 ? 3) 4) If II.3 had been unaffected by the trait, how could the genotypes of his children be explained, assuming no other changes in the pedigree? 5) Does the trait appear to be typically mendelian ? Explain your answer (you may argue for and against the proposition if you wish). Place an order with similar or related instructions NOW
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