In tomato plants, purple leaf color is controlled by a dominant allele A, and green leaf by a recessive allele a. At another locus, hairy leaf H is dominant to hairless leaf h. The genes for leaf color and leaf texture are separated by 16 m.u. on chromosome 5. On chromosome 4, a gene controlling leaf shape has two alleles: a dominant allele C that produces cut-leaf shape and a recessive allele c that produces potato-shaped leaf.

Fully explain the number and frequency of each phenotype class.

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 alleles mask the expression of recessive ones. In the context of the question, the inheritance of leaf color and texture in tomato plants follows these principles, allowing predictions about phenotype ratios based on allele combinations.

Linkage and Recombination

Linkage refers to the tendency of genes located close to each other on a chromosome to be inherited together. In this case, the genes for leaf color and texture are separated by 16 map units, indicating a certain frequency of recombination. Understanding linkage is crucial for predicting the frequency of different phenotype classes, as it affects how alleles assort during gamete formation.

Phenotypic Ratios

Phenotypic ratios describe the relative frequencies of different observable traits in the offspring resulting from a genetic cross. In this scenario, the phenotypes of tomato plants can be predicted by considering the combinations of alleles for leaf color, texture, and shape. By applying the principles of Mendelian inheritance and accounting for linkage, one can calculate the expected ratios of purple vs. green leaves, hairy vs. hairless texture, and cut vs. potato shape.