allele

Alternate form of a gene

gene variant

autosome

Chromosome that does NOT determine sex

#1-22 in humans

chromosome

Structure made of DNA and special proteins; carries genes

DNA

Deoxyribonucleic acid;

sequences in DNA are codes for making proteins

Dominant

Allele that exerts effect with just one copy;

“overpowers” recessive gene

gene

Sequence of DNA that has a known function;

encodes for a protein or turns another gene on/off

Gene pool

All of the genes in a population

genome

Complete set of genetic instructions; all of the A, T, C, and G’s in the DNA of an organism

genotype

Allele combination ex. Tt or tt

karyotype

Display of chromosomes in order of size

Mendelian trait

Determined by a single gene

Multifactorial trait

Determined by one or more genes and the

environment

Mutation

Change in a gene;could affect health, appearance or biochemistry

Pedigree

Diagram used to follow inheritance of a trait in a

family

Phenotype

Observable expression of allele combination

ex. Tall or short

polymorphism

A place in the genome that varies in 1% or more

of the population

recessive

An allele that exerts effect only when present

in two copies

RNA

Ribonucleic acid;many jobs including

helping cells to synthesize proteins

Sex chromosome

Chromosome that carries genes that determine sex

in humansXX or XY