Honors Biology: Genetics

Genetics

The study of genes and how they function.

Gergor Mendel

The father of modern genetics

Trait

A characteristic that an organism can pass on to its offspring through its genes.

Chromosome

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

Locus

The location of genes on a chromosome

Allele

Different forms of a gene

Dominate Allele

An allele that will be observed if one or both gene copies are this version.

Recessive Allele

An allele that will be observed only if both gene copies are this form

Homozygous Genotype

Both alleles are the same (AKA a hybrid)

Genotype

An allele inherited from the egg cell and the allele inherited from the sperm cell for a particluar gene

Homozygous dominant genotypes

Two alles that are the same and are both dominate

Homozygous recessive genotypes

Two alles that are the same and are both recessive

Heterozygous Genotype

A genotype with two different alleles

Phenotype

The appearance of a measurable trait resulting from the genotype of a particular gene

Punnett Sqaure

A chart that shows all the possible combinations of alleles that can result from a genetic cross

Mendel's Law of Segregation

The two copies of a gene segregate from each other during transmission from parent to offspring

Diploid Cells

Cells that have pairs of chromosomes

Haploid Cells

A cell containing only one set of chromosomes.

Medel's Law of Independent Assortment

Each pair of factors segregates independently of the other pairs

Dihybrid Cross

A cross between individuals that have different alleles for the same gene

Autosomal Traits

Traits influenced by a gene found on any of the autosomes

Autosomes

Any chromosome that is not a sex chromosome (1-22)

Sex-Linked Traits

Traits controlled by genes located on sex chromosomes.

X-linked

A gene located on the X chromosome

y-Linked

A gene located on the Y chromosome

Incomplete Dominance

The situation in which one allele is not completely dominant over another allele

Codominance

A condition in which neither of two alleles of a gene is dominant or recessive.

Pleiotropy

The ability of a single gene to have multiple effects.

Epistasis

A type of gene interaction in which one gene alters the phenotypic effects of another gene that is independently inherited.

Polygenic Trait

A trait controlled by two or more genes