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

deoxyribonucleic acid, a self-replicating material which is present in nearly all living organisms as the main constituent of chromosomes. It is the carrier of genetic information.

a unit of heredity which is transferred from a parent to offspring and is held to determine some characteristic of the offspring.

Dominant traits are those that are expressed or seen when a heterozygous genotype is present. Heterozygous just means having two different alleles for a gene. One is usually dominant while one is recessive. Remember, recessive alleles are masked by dominant alleles.

recessive trait. ... Recessive traits can be carried in a person's genes without appearing in that person. For example, a dark-haired person may have one gene for dark hair, which is a dominant trait, and one gene for light hair, which is recessive.

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.

an individual having two different alleles of a particular gene or genes, and so giving rise to varying offspring.

an individual having two identical alleles of a particular gene or genes and so breeding true for the corresponding characteristic.

Cells that tell to see if you are a girl or boy.

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. It is named after Reginald C. Punnett, who devised the approach. The diagram is used by biologists to determine the probability of an offspring having a particular genotype.