Genetics Definitions

genes

• Segments of DNA that code for specific traits or proteins.

chromosomes

• Thread-like structures made of DNA and proteins that carry genetic information.

autonomes

• Non-sex chromosomes that are the same in both males and females.

sex chromosomes

• Chromosomes (X and Y) that determine an organism's sex.

karyotype

• A visual representation of an organism’s complete set of chromosomes.

• DNA (Deoxyribonucleic Acid)

• A molecule that carries genetic instructions for life.

protines

• Molecules made of amino acids that perform various functions in the body.

codon

• A sequence of three DNA or RNA bases that codes for a specific amino acid.

mitosis

• A type of cell division that produces two identical daughter cells for growth and repair.

meiosis

• A type of cell division that produces gametes (sperm and eggs) with half the usual number of chromosomes.

heredity

the passing of traits from one generation to another

traits

characteristics that can be passed from one generation to another (eg. eye colour)

dominant trait

more likely to be inherited due to it being the stronger dominant gene

recessive trait

the weaker trait which needs two copies to be passed down

adenine binds with…

thymine

thymine binds with…

adeline

guanine binds with

cytosine

cytosine binds with…

guanine

alleles

one of two or more versions of a genetic sequence at a particular region on a chromosome

types of allele dominance

• simple dominant

• sex-linked

• co-dominance

• incomplete dominance

non-disjunction

genotype

• the genetic make up of an organism

• describes genes responsible for a trait or characteristic

phenotype

• the physical appearance of an organism

heterozygous

when a genotype has two different alleles (Hh) - hetero means different

homozygous

genotype has two identical alleles (HH or hh) - homo means same

co-dominance

both alleles are equally dominant and show up

incomplete dominance

a mix of the dominant and recessive alleles will apear

sex-linked

controlled by genes on the X or Y chromosome

simple dominant/recessive

controlled by a single gene

human blood type is determined by…

3 alleles of a gene, 2 of these are co-dominant in humans

type A blood

genotypes IA IA or IA i

type B blood

genotypes IB IB or IB i

type AB blood

genotypes IA IB

type O blood

genotypes i i

pedigrees

charts that represent inheritance patterns in family trees

inheritance pattern - autosomal dominant

each affected person usually has an affected parent; occurs in every generation

inheritance pattern - autosomal recessive

both parents of an affected person are carriers not typically seen in every generation