CM-UY 1004 Lecture Notes - Lecture 7: Nondisjunction, Zygosity, Dihybrid Cross
Document Summary
A gene represents the genetic material on a chromosome that contains the instructions for creating a particular trait. An allele is one of the several varieties of a gene. In some plants there are two alleles of the gene for stem length. A locus refers to the location on a chromosome where a gene is located. Every gene has a unique locus on a particular chromosome. Homologous chromosomes refer to a pair of chromosomes (a homologous pair) that contains the same genetic information, gene for gene. At any one particular locus, the two genes on a pair of homologous chromosomes ( a gene pair) might represent two different alleles for that gene because they originated from different parents. If the two alleles inherited for a gene (each one of the two homologous chromosomes) are different one allele may be recessive and the other might be dominant. The trait by the dominant allele is the actual one that is expressed.
