Genes and Alleles

Locus

A specific location of a gene in a chromosome.

Allele

An alternative form of a gene for a specific trait that is located on the same locus of a pair of homologous chromosome

Homologous chromosomes are a set of one maternal and one paternal chromosome that pair up with each other inside a cell

Heterozygote : Alleles at loci of a pair of homologous chromosomes are different

Homozygous dominant: On these two loci, the genes are homozygous because of their similar dominant allele.

Homozygous recessive: On these two loci, the genes are homozygous because of their similar recessive allele.

Centromeres are typically located in the central area of a chromosome

Each gene is located on the same locus of :

A pair of homologous chromosomes.

Dominant alleles are written in

Capital letter

Recessive alleles are written in

Small letter