GENETICS

How many chromosomes does an average person have?

Everyone should have 46 chromosomes (a set of 23 from each parent)

Allelles

Different forms of the same gene

Phenotype

A trait that is shown on an organism is known as it’s phenotype

eg. brown hair, dark skin, blue eyes

Genotype

a combination of alleles inherited from one parent

• two alleles of particular gene are the same → homozygus

• two alles are different → hetrozyguys

Dominant

• the trait that overides the other is the dominant trait

Recessive

• trait that is being overridden => recessive

Punnet square

a diagram used to predict the outcome of a genetic cross

Incomplete Dominance

when an organism has both alleles expressed at the same time as a blend of the parents’ characteristics

Co-dominance

an offspring that shows both parents’ characteristics

4 major blood groups

• derminted by presence or __ of A & B antigens

• type a

• type b

• type AB

• type o

homozygus

two allels of a particular gene are the same

heterozygus

two alleles of a particular gene are different. there are two types: dominant and recessive

pure breed

an organism whose alleles for a certian trait are teh same from bth parents (must be homozygus recessive or dominant)

hybrid

an organism whose alleles from each parent are different (must be hetrozygus)

complete dominance

when one allel completly masks the affect of the other allele in a hetrozygus conditon