15 - 18: Genetics definitions

Gene

Piece of DNA that codes for a protein

Genetic Engineering

Artificial manipulation of a gene

Coding DNA

Has genetic instructions to produce a protein

Non-coding DNA

Has genetic instructions that does not produce a protein

Species

Group of organisms that can reproduce together to produce fertile offspring

Allele

Alternative form of a gene

Heterozygous

Two different alleles are present

Homozygous

Identical alleles are present

Evolution

Genetic changes in a species over a period of time in response to environmental changes

Tissue culture

Growing cells in a nutrient medium

Dominant

An allele masks the effect of another allele

Recessive

Allele masked by the dominant allele

Mendel’s Law of Segregation

Each trait is controlled by a pair of alleles

These alleles separate during gamete formation

Each gamete contains only one allele for each trait

Mendel’s Law of Independent Assortment

Each member of one pair of alleles can combine with either member of another pair at gamete formation

Inherited

Passed on from parents to offspring using genes

Genotype

Genetic makeup of an organism

Phenotype

The physical expression of a gene

Sex-linked

Gene located on the sex (X or Y) chromosome

Heredity

Passing on of characteristics from one generation to the next

DNA profiling

Generating a pattern of bands from a DNA sample

Genetic screening

Test to show presence or absence of a gene

Incomplete dominance

When both alleles are expressed