Alleles

Alleles are different forms of a gene that can occupy the same locus on a chromosome. They are responsible for the variation in inherited traits among individuals.

Key Points to Remember

1. Alleles are different versions of a gene.
2. They can be dominant or recessive.
3. Alleles are located at the same position (locus) on homologous chromosomes.
4. They determine the traits and characteristics of an organism.
5. Alleles can be homozygous (having two identical alleles) or heterozygous (having two different alleles).

Study Guide

Here are some important concepts to understand about alleles:

• Genes: Genes are the units of heredity and are made up of DNA. They determine specific traits in an organism.
• Allele Pairs: Each individual carries two alleles for a particular gene, one from each parent.
• Dominant and Recessive Alleles: Dominant alleles mask the expression of recessive alleles. A dominant allele will be expressed in the phenotype if it is present.
• Homozygous and Heterozygous: Homozygous individuals have two identical alleles for a particular gene, while heterozygous individuals have two different alleles.
• Crossing Over: During meiosis, alleles can be exchanged between homologous chromosomes, leading to genetic recombination.
• Mendel's Laws: Gregor Mendel's laws of segregation and independent assortment describe how alleles are inherited and how they segregate and recombine during gamete formation.

Understanding alleles is crucial in comprehending genetics and inheritance patterns in living organisms.