Chapter 10: Genes and Chromosomes. Section 1: The Chromosome Theory of Heredity. The Chromosome Theory of Heredity. Mendel’s work was incomplete because he never asked an important questions that was the logical outcome of his work Where in the cell are the factors that control heredity?
Section 1: The Chromosome Theory of Heredity
These chromosomes are from a mouse cell. Chromosomes, which are located in the nucleus of a cell, are precisely separated during cell division – an indication that they contain something extremely critical to the cell.
According to Mendel’s hypothesis, the two factors for each trait are segregated during gamete formation. Thus gametes have only one factor for each trait. This hypothesis is supported by the observations that homologous chromosomes are separated during meiosis and that gametes contain only one of the chromosomes of each homologous pair.
According to Sutton’s chromosome theory of heredity, genes are located on the chromosomes. Homologous chromosomes have alleles for the same traits. These alleles may be the same on both homologous chromosomes or they may be different.
Section 2: Mutations
Mutations in genes that regulate development resulted in extra hind legs on this frog.
Section 3: Regulation of Gene Expression