Genetic Inheritance case study
Magoo Inheritance Magoos are a species of monsters that exhibit the same patterns of inheritance as humans. A magoo can be blue, yellow or green and may or may not have horns, wings or a tail. When a magoo smiles, they may appear friendly, with a mouth full of teeth similar to ours, or scary with sharp fangs that are several inches long. Some magoos have both teeth and fangs which is a highly regarded trait in their society. Most magoos have only two eyes, but occasionally there will be some that have three. Answer the following questions about the inheritance of traits in magoos. Problem A : For magoos, having wings is dominant over not having wings. In a family of magoos, Meg and her father, Mike, both have wings while her brother, Marvin, and Mother, Maria do not. What are the genotypes for each member of this magoo family? Meg Marvin Maria Mike Problem B : The color of a magoo is either blue (B), yellow (Y) or an intermediate phenotype of green. What would be the genotype of a green magoo? If two green magoos had children, what would be the chances their child would be blue? What would be the genotypic ratio of their children? Since neither blue nor yellow is dominant over the other, and some magoos are green, what pattern of inheritance does this trait display? Problem C : For magoos, a single gene controls their dentition (the type and arrangement of teeth). However, there are several teeth phenotypes. Some Magoos have square teeth, with having square teeth (D S ) being dominant to not having square teeth (d). Other Magoos have fangs, with fangs (D F ) being dominant to no fangs (d). However, there are magoos that have both square teeth AND fangs and magoos with neither. Meg, a magoo with only fangs, has a problem – she’s not sure if Mario or Matt is the father of her child, Malia (maybe a call to Maury is in order!). Matt has the coveted smile of teeth and fangs, while Mario only has teeth. Malia is unlike anyone else in this scenario since she has neither teeth nor fangs. How would you describe the trait of having teeth and fangs? What is Malia’s genotype? What is Meg’s genotype? Is it possible for Mario to be Malia’s father? Explain using Mario’s genotype for support. Is it possible for Matt to be Malia’s father? Explain using Matt’s genotype for support. If Meg had another child with Malia’s father, what would be the chances that child would also have no teeth or fangs? Problem D : The number of eyes a magoo has is a sex-linked trait carried on the X chromosomes. Male magoos inherit two X chromosomes, while females inherit an X and a Y . The dominant allele codes for 3 eyes while the recessive trait is to have 2 eyes. Marvin is a heterozygous male with 3 eyes and has offspring with Melissa, a 2-eyed female. What is Marvin’s genotype? What is Melissa’s genotype? If they have a boy, what are the chances he will have 3-eyes? If they have a girl, What are the chances she will have 2-eyes? What percentage of their offspring will be carriers for having 2-eyes? Would having two eyes be more often seen in male or female magoos? Explain. Problem E: Matt comes from a family with a history of albinism which is a recessive genetic condition which causes them to lack pigmentation and appear white. His partner, Maddie, also has albino relatives. What type of genetic testing would be recommended for these individuals? If Maddie and Matt are both carriers for the gene, what would be the chance their child will be albino? Problem F: Morgan (M) is unsure of the father of her child (C) so she decided to appear on the Maury show to determine paternity. She brings two potential fathers with her, the first one is Max (F1) and the other is Mo (F2). Given the test results below, who is the father of Morgan’s child? Be able to explain.