Heredity and Heredity and GeneticsGenetics

How it all works DominantDominant is the expressed trait. is the expressed trait. (That (That

means the trait we see. So it gets a means the trait we see. So it gets a capital letter.)capital letter.)

RecessiveRecessive is the unexpressed trait. is the unexpressed trait. (That’s the one we don’t see. So it (That’s the one we don’t see. So it gets a lower case letter.)gets a lower case letter.)

CodominantCodominant is when both traits is when both traits are equally dominant and are are equally dominant and are equally expressed. equally expressed.

What is Genetics?What is Genetics?

Genetics explains how traits are passed Genetics explains how traits are passed on from generation to generation.on from generation to generation.

Traits are either Dominant or RecessiveTraits are either Dominant or Recessive (Look at the Laboratory Investigation sheet)(Look at the Laboratory Investigation sheet)

Tongue Roller-Tongue Roller- Widow’s peakWidow’s peak Hitchhikers thumb-Hitchhikers thumb- Red/not hair-Red/not hair- Hand Clasp-Hand Clasp- Earlobes Free-Earlobes Free- Eye ColorEye Color

Who is Mendel and What Does Who is Mendel and What Does a Pea Plant Have to do with a Pea Plant Have to do with

ME?ME? Mendel became the father of genetics. Mendel became the father of genetics. He did not realize it then, but his study of pea He did not realize it then, but his study of pea

characteristics or traits gave us the basics for genetics characteristics or traits gave us the basics for genetics today.today.

He studied traits like how tall they grew, the color He studied traits like how tall they grew, the color of seeds, and the shape of the seedsof seeds, and the shape of the seeds..

He tried to cross traits to see what He tried to cross traits to see what would happen. (He found things like would happen. (He found things like a tall and a short made 4 tall.. This a tall and a short made 4 tall.. This led to the idea of dominant and led to the idea of dominant and recessive.recessive.

The The GenGenotype is the “otype is the “genegene” make-up of ” make-up of an organism.an organism.

The The PhPhenotype is the “enotype is the “phphysicalysical” look that the genes created.

What is his phenotype and What is his phenotype and genotype?genotype?

Dark Hair –BB or BbDark Hair –BB or Bb

Light Hair-bbLight Hair-bb

Pairs- the traits are put is pairs: one from mom Pairs- the traits are put is pairs: one from mom and one from pops. The pairs are either and one from pops. The pairs are either heterozygous ( (different Dddifferent Dd) or ) or homozygous (same DD or dd(same DD or dd).).

We use the We use the punnett square to figure out what to figure out what an offspring's genotype and phenotype will an offspring's genotype and phenotype will be. Draw this on your graph paper.be. Draw this on your graph paper.

d dd d

DD

ddDd dd

Now try this:Now try this:

Gg gg

dd DD

continuecontinue

Hh hh

Ss Ss

Genotype and PhenotypesGenotype and Phenotypes

H is blue, h is yellow: What is Hh?H is blue, h is yellow: What is Hh?

T is tall, t is short: what is TT? Tt? tt?T is tall, t is short: what is TT? Tt? tt?

What is the only way to make the What is the only way to make the recessive gene show?recessive gene show?

Word Bank for Heredity QuizWord Bank for Heredity QuizTrait heterozygous allele

Allele Genotype

Phenotype homozygous allele

Dominant allele heredity

Recessive allele genetics