A geneticist from an alien planet that prohibits genetic research brought with him to Earth two pure-breeding lines of frogs. One line croaks by uttering 'rib-it rib-it' and has purple eyes. The other line croaks more softly by muttering 'knee-deep knee-deep' and has green eyes. With a newfound freedom of inquiry, the geneticist mated the two types of frogs, producing F₁ frogs that were all utterers and had blue eyes. A large F₂ generation then yielded the following ratios: 27/64 blue-eyed, 'rib-it' utterer 12/64 green-eyed, 'rib-it' utterer 9/64 blue-eyed, 'knee-deep' mutterer 9/64 purple-eyed, 'rib-it' utterer 4/64 green-eyed, 'knee-deep' mutterer 3/64 purple-eyed, 'knee-deep' mutterer How many total gene pairs are involved in the inheritance of both traits? Support your answer.

Key Concepts

Mendelian Genetics

Mendelian genetics is the study of how traits are inherited through generations based on the principles established by Gregor Mendel. It involves understanding dominant and recessive alleles, where dominant traits mask the expression of recessive ones. In this scenario, the traits of croaking and eye color can be analyzed using Mendel's laws of segregation and independent assortment to determine how they are passed from parents to offspring.

Phenotypic Ratios

Phenotypic ratios represent the relative frequencies of different observable traits in the offspring of a genetic cross. In the given F₂ generation, the ratios of blue-eyed and green-eyed frogs, as well as their croaking patterns, can be analyzed to infer the underlying genetic mechanisms. By calculating these ratios, one can deduce the number of gene pairs involved in the inheritance of the traits, as they reflect the combinations of alleles inherited from the parent frogs.

Gene Interaction

Gene interaction refers to the way different genes influence each other's expression and the resulting phenotype. In this case, the traits of croaking and eye color may be controlled by multiple genes that interact in complex ways. Understanding whether these traits are governed by a single gene or multiple gene pairs is crucial for determining the total number of gene pairs involved in the inheritance of both traits, as seen in the observed phenotypic ratios.