Genetics

HeredityThe transmission of characteristics from one generation

to the next.Genetics is the study of how heredity works.Gregor Mendel discovered particulate inheritance

Who was Mendel (1822-1884)?

Gregor Mendel was an Augustinian monk, and avid gardener and bee keeper, an experimental physicist, a teacher, and the founder of modern genetics.

The HomunculusPreformationism – a tiny human called

a homunculus is present in each sperm.

Mendel discovered particulate inheritance: think meiosis

DNAThe molecule (particle) of heredity

ChromosomesLong strands of DNA wrapped around histones

Karyotype – boy or girl?

GenesExist on chromosomesTurn one on and a protein is

made

AlleleAlternate forms of same gene

A

a

More vocab! Genotype – which set of alleles (Aa) Phenotype – which trait (purple flower) Dominant – shows trait if AA or Aa Recessive – shows trait only if aa Homozygous – alleles are identical (AA or aa) Heterozygous – alleles are different (Aa)

QuestionAre dominant phenotypes more common than recessive

phenotypes?

Your hypothesis? Yes / No

Eye ColorBrown eyes are dominant to blue eyes.

What is your Phenotype?

Widow’s PeakA widow’s peak is dominant to a straight hairline

Hitch Hicker’s Thumb A hitch hiker’s thumb is a recessive trait.

Bent Little FingerA bent little finger is dominant to a straight one. Hold

your hand out in front of you with your fingers together.

EarlobesUnattached earlobes is dominant to attached earlobes.

Tongue CurlIf you can curl your tongue, you have the dominant

allele.

FrecklesHaving freckles is dominant.

Hairy KnucklesAny hair on your knuckles means you are dominant.

Interlocking FingersLeft thumb over right thumb is dominant to right thumb

over left thumb.

Mendelian TraitsTrait Genotype PhenotypeEye Color B? or bb Brown or blueWidow’s Peak W? or ww Present or absentHitch Hiker’s Thumb H? or hh Can’t or can bendBent Little Finger L? or ll Bent or straightEarlobe E? or ee Unattached or

attachedTongue Curl T? or tt Curl or notFreckles F? or ff Present or absentHairy Knuckles K? or kk Present or absentInterlocking Fingers P? or pp L over R or R over L

Homework Find phenotype for your parents Find phenotype for all siblings Add information to your table Due Thursday