Transcript Slide 1

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 70- 90% of the population have freehanging 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 Earlobe
Attached ee
Free Earlobe
Inherited Traits
Tongue Roller
TT or Tt
tt
Hair Type
Curly Hair
CC

Wavy Hair
Cc


cc
Straight Hair
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.
2.
3.
To predict evolutionary success, we study the
variability of different phenotypes and genotypes
to provide an overview of the population.
Gene frequencies are at the heart of evolution
and speciation.
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?
Trait
Form 1
Form 2
Gender
50%
50%
Earlobes
Free 70-90%
Attached 10-30%
Tongue R.
Roll 70-90%
Non R. 10-30%
PTC
Taster 70-90%
Non T. 10-30%
Thumb Ext.
Straight 64-75%
Hitch H. 25-36%
Hair
Curly – More
Straight - Less
Hairline
Widows – More
Straight -Less