You and Your Genes Background 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 her mother’s eyes,” or, “He has his father’s chin”. People are noticing the inherited 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 Genes Some 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 Genes Background Information: % Humans have numerous traits, but some traits are more frequently seen. Between % 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 Hair Mid - 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 DdBlond dd

PTC  PTC GENE PTC GENE Taster PP or PpNon – 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. cheetah

Frequency Chart Do our results match the general population? Trait Form 1 Form 2 Gender50%50% Earlobes Free 70-90% Attached 10-30% Tongue R. Roll 70-90% Non R % PTC Taster 70-90% Non T % Thumb Ext. Straight 64-75% Hitch H % Hair Curly – More Straight - Less Hairline Widows – More Straight -Less