You and a friend are studying dewlap color in a species of lizards. Red dewlaps
ID: 146430 • Letter: Y
Question
You and a friend are studying dewlap color in a species of lizards. Red dewlaps are most common, but some lizards have yellow, pink, or white dewlaps. Your friend thinks that dewlap color may be controlled by a single gene with many alleles, and that red is the dominant allele. You think that dewlap color may be caused by the interaction of two genes to create novel phenotypes. Assume you can produce pure-breeding lizards of each dewlap color. (1) What phenotypic ratio(s) would you expect if the trait is coded by one gene with many alleles? (2) What phenotypic ratio(s) would you expect if the trait is coded by the interaction of two genes? You and a friend are studying dewlap color in a species of lizards. Red dewlaps are most common, but some lizards have yellow, pink, or white dewlaps. Your friend thinks that dewlap color may be controlled by a single gene with many alleles, and that red is the dominant allele. You think that dewlap color may be caused by the interaction of two genes to create novel phenotypes. Assume you can produce pure-breeding lizards of each dewlap color. (1) What phenotypic ratio(s) would you expect if the trait is coded by one gene with many alleles? (2) What phenotypic ratio(s) would you expect if the trait is coded by the interaction of two genes? You and a friend are studying dewlap color in a species of lizards. Red dewlaps are most common, but some lizards have yellow, pink, or white dewlaps. Your friend thinks that dewlap color may be controlled by a single gene with many alleles, and that red is the dominant allele. You think that dewlap color may be caused by the interaction of two genes to create novel phenotypes. Assume you can produce pure-breeding lizards of each dewlap color. (1) What phenotypic ratio(s) would you expect if the trait is coded by one gene with many alleles? (2) What phenotypic ratio(s) would you expect if the trait is coded by the interaction of two genes?Explanation / Answer
Please find the answers below:
Answer 1: According to the information, the lizards display a variety of colors and this observation depends upon the number of dominant alleles a lizard inherits. More is the number of these alleles, darker is the color of lizard. Since the lizards display at least 4 phenotypes, it is very likely that they are inherited in response of two genes each having two alleles. Thus, this becomes a Mendelian dihybrid cross. Thus, if two pure-breeding lizards are crossed, the pheotypic ratio to be expected will be 9:3:3:1::red: yellow: pink: white colors.
Answer 2: If the trait produced results from interaction of two genes, the phenotypic ratio will change depending upon the nature of interaction. Thus, the final ratio can be either 1:1:1:1 or 13:1 depending upon the nature of interaction.
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