Genome, Gene, Allele & Inheritance

Gene

A section of DNA that codes for a specific trait.

Allele

A specific variation or version of a gene.

Gene Locus

The specific physical location of a gene on a chromosome.

Maternal Chromosome

The chromosome inherited from the biological mother.

Paternal Chromosome

The chromosome inherited from the biological father.

Genotype

The specific genetic makeup or allele combination (e.g., Bb).

Phenotype

The physical expression or observable trait (e.g., Brown eyes).

Dominant Allele

An allele that masks a recessive one; shows up if even one copy is present.

Recessive Allele

An allele only expressed if two copies are present.

Homozygous

Having two identical alleles for a gene (e.g., BB or bb).

Heterozygous

Having two different alleles for a gene (e.g., Bb).

Co-Dominance

Both alleles are fully and equally expressed together (e.g., speckled chicken).

Incomplete Dominance

Alleles blend to create an intermediate phenotype (e.g., Red + White = Pink flower).

Complete Dominance

One allele totally hides the other in a heterozygote.

Polygenetic

A trait controlled by multiple genes acting together (e.g., human height).

Monogenetic

A trait controlled by only a single gene (e.g., cystic fibrosis).

Epigenetics

Changes in gene expression without altering the underlying DNA sequence.

Sex-linked Genotypes

Genotypes for genes located on the sex chromosomes (X or Y).

X Chromosome

The larger sex chromosome found in both males and females.

Y Chromosome

The smaller sex chromosome found only in biological males.