Genetics,Study of how traits are passed from parents to offspring Trait,A specific characteristic (ex: eye color) Gene,A segment of DNA that controls a trait Allele,Different forms of a gene Genotype,The genetic makeup (letters like BB, Bb) Phenotype,The

Genetics

Study of how traits are passed from parents to offspring

Trait

A specific characteristic (ex: eye color)

Gene

A segment of DNA that controls a trait

Allele

Different forms of a gene

Genotype

The genetic makeup (letters like BB, Bb)

Phenotype

The physical appearance (what you see)

Homozygous

Two identical alleles (BB or bb)

Heterozygous

Two different alleles (Bb)

Dominant allele

An allele that masks another (capital letter)

Recessive allele

Only shows if both alleles are recessive (bb)

True-breeding

Always produces same trait (homozygous)

Hybrid

Heterozygous organism (Bb)

Gamete

A sex cell (sperm or egg) with one allele

Fertilization

Joining of two gametes

P generation

Original parents

F1 generation

First offspring

Law of Dominance

Dominant allele hides recessive

Law of Segregation

Alleles separate during gamete formation

BB genotype

Shows dominant trait

Bb genotype

Shows dominant trait

bb genotype

Shows recessive trait

Bb x Bb genotypes

1 BB : 2 Bb : 1 bb

Bb x Bb phenotypes

3 dominant : 1 recessive

Bb x bb genotypes

2 Bb : 2 bb

Bb x bb phenotypes

1 dominant : 1 recessive

BB x bb result

All Bb

BB x Bb result

2 BB : 2 Bb

If an organism has Bb what is the phenotype?

Dominant trait

What genotype shows recessive trait?

bb

What does each parent pass to offspring?

One allele

What determines phenotype?

Dominant allele

If 2 heterozygous parents cross

25% recessive

If one parent is homozygous dominant and one recessive

100% heterozygous

If both parents are homozygous recessive

100% recessive

If one parent is Bb and other BB

0% recessive

Purebred

Homozygous

Mixed traits

Heterozygous

Capital letter means

Dominant

Lowercase letter means

Recessive