a threadlike structure of nucleic acids and protein found in the nucleus of most living cells, carrying genetic information in the form of genes.

DNA or deoxyribonucleic acid is a long molecule that contains our unique genetic code. Like a recipe book it holds the instructions for making all the proteins in our bodies.

A gene is a sequence of nucleotides in DNA or RNA that encodes the synthesis of a gene product, either RNA or protein.

Dominance, in genetics, is the phenomenon of one variant of a gene on a chromosome masking or overriding the effect of a different variant of the same gene on the other copy of the chromosome. The first variant is termed dominant and the second recessive.

A recessive trait is a trait that is expressed when an organism has two recessive alleles, or forms of a gene.

the passing on of physical or mental characteristics genetically from one generation to another.

one of two or more alternative forms of a gene that arise by mutation and are found at the same place on a chromosome.

having two different alleles of a particular gene or genes.

Homozygous is a word that refers to a particular gene that has identical alleles on both homologous chromosomes. It is referred to by two capital letters (XX) for a dominant trait, and two lowercase letters (xx) for a recessive trait.

The formation of sex cells is a central part of human reproduction: In fertilization, an egg cell and a sperm cell combine.

the set of observable characteristics of an individual resulting from the interaction of its genotype with the environment.

the genetic constitution of an individual organism.

The Punnett square is a square diagram that is used to predict the genotypes of a particular cross or breeding experiment.