Science

Heredity

The passing of traits from parents to offspring.

Genetics

The science that deals with the study of heredity.

DNA

A double helix molecule that carries genetic information.

The sides of DNA

Made up of sugar and phosphate.

The steps of DNA

Made up of nitrogen base pairs.

Guanine

One of the nitrogen bases in DNA, represented as 'G'.

Cytosine

One of the nitrogen bases in DNA, represented as 'C'.

Adenine

One of the nitrogen bases in DNA, represented as 'A'.

Thymine

One of the nitrogen bases in DNA, represented as 'T'.

Gene

A length of DNA that codes for a particular protein.

Histones

Special proteins that tightly coil around DNA to form chromosomes.

Chromosomes

Structures found inside the nucleus of the cell that contain DNA.

Mitosis

The process of replication and dividing of cells.

Diploid

Having two complete sets of chromosomes (double).

Haploid

Having a single set of unpaired chromosomes (half).

Meiosis

The process by which sex cells divide and shuffle their genetic material.

Sex chromosomes

Chromosomes that determine the sex of an individual.

Autosomes

The first 22 chromosomes in humans, not involved in determining sex.

Sex chromosomes

The 23rd pair of chromosomes that determine the sex of an individual.

Variation

The combination of sex cells during fertilization.

Mutations

Permanent changes in DNA that may lead to physical manifestations at the biochemical level.

Alleles

Genes that have two or more variations.

Genotype

The actual set of genes carried by an organism.

Phenotype

The physical characteristics exhibited by an organism.

Homozygous

Having two identical alleles for a particular gene.

Heterozygous

Having two different alleles for a particular gene.

Dominant alleles

Alleles that have a strong influence on the phenotype.

Recessive alleles

Alleles that have a weak influence on the phenotype.

Somatic mutation

Mutations that occur in any body cell except for reproductive cells and are not passed on to offspring.

Germ mutation

Mutations that occur in reproductive cells and may be passed to the next generation.

Gregor Mendel

Proposed the non-Mendelian inheritance in 1865 through experiments with pea plants.

Independent assortment

The principle that traits are inherited independently of one another.

Segregation

The separation of contrasting traits into different offspring.

Josef Kolreuter

Conducted experiments with red and white carnations, producing pink flowers through blending in 1760.

Incomplete dominance

A situation where one allele does not fully express its phenotype in a homozygous individual.

Codominance

A scenario where both alleles are equally strong and visible in the hybrid genotype.

Multiple alleles

A situation where a gene has more than two alleles.

Epistasis

Interaction between two or more genes that affects a single phenotype.

Modifier

One gene's action is modified by one or several other genes.

Epistatic

The gene that modifies the action of another gene.

Hypostatic

The gene that is modified by another gene.

Thomas Hunt Morgan

Studied genetic variation in fruit flies in 1910.