1 5 pts You what to identify dominantrecessive relationship

1. (5 pts) You what to identify dominant/recessive relationship for skin color in a new frog species that you found in the rain forest. (Assume that one autosomal gene controls skin color). All of the frogs of this species have either bright blue or yellow skin. A bright blue male and a bright blue female produce only bright blue offspring. However, a bright blue male and a yellow female produce a 3:1 ratio of yellow to bright blue offspring. a. Which allele is dominant and which is recessive. How can you tell? b. Propose a molecular mechanism to explain the yellow and blue skin color in this frog species. 2. (5 pts) Match the type of phenotypic change below with the type of genetic change most likely to cause it. Each type of genetic change may be used more than once, or may not be used at all. A. mutation within a gene B. gene duplication C. mutation in a regulatory region D. exon shuffling E. horizontal gene transfer B-catenin, a protein involved in cell-cell adhesion, acquires a kinase domain. The retroviral genes, gag and pol, are found in the human genome. A protein that was normally expressed in the mammary gland is now expressed in the brain. odorant receptors constitute a large gene family. A deletion of three nucleotides in the B-globin gene results in a misfolding of the protein.

Solution

1) a) As the crossing of bright blue male frogs with bright blue females results in only bright blue offsprings, it means it is a recessive trait.

This is further supported by the next crossing mentioned in the example. Bright blue male when crossed with yellow female results in 3:1 ratio of yellow to blue (yellow appears more in the population) which means that yellow is dominant trait and Bright blue color is the recessive trait.

1b) The molecular mechanism can be explained by the crossing over occurring at the meiosis cell division resulting in exchange of chromatids from maternal and paternal sides resulting in recombinant offspring.