Biology keywords 3 (allele, genotype, phenotype)

Allele

An alternative form of a gene.

Phenotype

Characteristics of an organism expressed (or seen). E.g. eye colour, hair colour

Genotype

The genes or alleles that are carried to give the particular feature (PHENOTYPE). One allele comes from each parent. Lower and upper case letters are used to represent this. E.g. BB, Bb, bb

Homozygous

Having two alleles the same for a particular gene and genotype. E.g BB or bb

Heterozygous

having two different alleles for a particular gene (genotype). E.g. Bb

Dominant

An allele that is always expressed and seen in the phenotype. E.g BB or Bb

Even if there is only one allele that is dominant, it is still expressed in the phenotype (feature)

Recessive

An allele that will not be expressed unless BOTH alleles are in the recessive form. E.g. bb

If one allele is DOMINANT, the dominant allele will be expressed over it.

Gene

A section of DNA