GENETICS….. FINALLY!

We all have different traits/characteristics

Traits – eye color, hair color and texture, height, etc.

Our genes that we inherit from our parents determine our traits.

Sections of DNA that determine a particular trait.

Example: Hair color or eye color

We inherit 2 genes for any particular trait – one from dad and one from mom.

Have the same ‘trait’ in the same place on a chromosome pair. This is universal among a species.

If the gene for hair color is on chromosome 5 in one person, it will be on chromosome 5, in the same place for EVERY person.

Different forms of a gene for a particular trait.

Example: Hair texture – curly or straight What are the alleles for hair color?

Both alleles for a particular trait are the same.

Example: B = brown eye gene and b = blue eye

gene BB = homozygous for brown eyes bb = homozygous for blue eyes

The alleles for a particular trait are different.

Example – Bb – heterozygous (hybrid) brown

eyes

An allele that is fully expressed in a heterozygous pair

Traits that will ONLY be expressed if both alleles are present.

Phenotype vs Genotype

A PHENOTYPE is how the traits appear. Remember: Ph-Physical appearance

A GENOTYPE refers to your genes

For example, someone with the phenotype brown eyes can have the genotype Bb. They are known as a ‘carrier’ because they carry the gene for blue eyes.

1822-1884

Predicts the results of genetic crosses

What is the result of a mate between a hybrid tongue roller and a non-tongue roller? R=tongue roller r = non-tongue roller

Traits that are neither dominant or recessive. Offspring receives a blend of each parents traits.

Example: Red snap dragons are crossed with

white snap dragons to make pink snap dragons.