You and Your GenesBackground

Have you ever noticed that sisters look alike? Or have you even

had difficulty telling them apart. Their inherited traits are what make

their physical appearance so similar. An inherited trait is a particular

genetically determined characteristic or quality that distinguishes

somebody. The traits of children are determined by the traits passed

on from their parents. This is why we often hear, “She has hermother’s eyes,” or, “He has his father’s chin”. People are

noticing theinherited traits.

You and Your Genes

Background (continued)It is often easy to determine inherited traits in family members, but

what about traits that are often unnoticed? You may even possess

many of the same traits as your classmates although you are not

directly related to those individuals. Parent organisms pass traits to their offspring so there are often similar characteristics seen in both parent and offspring.

You and Your GenesSome Human Inherited Traits include:* Ability to roll your tongue or not* Attached or unattached earlobes* Dimples or freckles* Naturally curly or straight hair* Hitchhiker’s or straight thumb* Color-blindness or normal color vision* Widow’s peak or straight hairline* Color of skin and hair* Cleft or smooth chin

You and Your GenesBackground Information:Humans have numerous traits, but some traits are more frequently seen. Between 70- 90% 70- 90% of the population have free-hanging earlobes, can roll their tongue, are right-handed and can taste PTC (a bitter tasting chemical that can be placed on the tongue). Because these traits occur most often within the population they are called high frequency traits. The rate of frequency is a statistical term that helps scientists determine how often an inherited trait occurs. Frequency is important in discovering how much of the population differs (or is similar) from the whole.

Population Genetics

Today we are studying population genetics.

Population genetics is the study of the frequency and interaction of alleles and genes in populations.

Mid – Digit HairMid - Digit Hair HH Hh No mid-digit hair hh

Inherited Traits

Widows Peak WW or Ww No Widows Peak

ww

Inherited Traits

Earlobes

Free EE or Ee Attached ee

Attached Earlobe Free Earlobe

Inherited Traits

Tongue Roller

TT or Tt tt

Hair Type

Curly Hair

CC

Wavy Hair

Cc

Straight Hair

cc

Freckles FF or Ff or No Freckles ff

Inherited Traits

Thumb Extension

Straight SS or Ss Hitchhiker ss

Inherited Traits

Chin Structure

Cleft Chin CC or Cc No Cleft Chin cc

Eye Color

Non Blue BB or Bb Blue bb

Hair Color

Dark Hair DD or Dd Blond dd

PTC

PTC GENE

Taster PP or Pp Non – Taster pp

You and Your Genes

Did the majority of the students in the class

Population show the dominant form of each high frequency trait? Why or Why not?

You and Your Genes

Is there a pattern in the traits expressed in our classroom population?

You and Your Genes

Why would a scientist study gene frequency in a population?1.To predict evolutionary success, we study the variability of different phenotypes and genotypes to provide an overview of the population.

2.Gene frequencies are at the heart of evolution and speciation.

3.To study variability of a species. The greater the variability the more successful the species. The cheetah has low variability and has struggled lately to survive as a species.

Frequency Chart Do our results match the general population?

TraitTrait Form 1Form 1 Form 2Form 2GenderGender 50%50% 50%50%

EarlobesEarlobes Free 70-90%Free 70-90% Attached 10-Attached 10-30%30%

Tongue R.Tongue R. Roll 70-90%Roll 70-90% Non R. 10-30%Non R. 10-30%

PTC PTC Taster 70-90%Taster 70-90% Non T. 10-30%Non T. 10-30%

Thumb Ext.Thumb Ext. Straight 64-Straight 64-75%75%

Hitch H. 25-Hitch H. 25-36%36%

HairHair Curly – More Curly – More Straight - LessStraight - Less

HairlineHairline Widows – MoreWidows – More Straight -LessStraight -Less