Transcript Genetic Traits

EQ: What are genetic traits?
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Genetics: study of heredity
Heredity: genetic information is passed from one generation to
the next
Gene: provide the instructions on what the plant or animal will
look like, how it will survive, and how it will interact with its
surroundings
Chromosomes: the structures in the nucleus that hold the
information (DNA) from our parents
Inherited Traits: characteristics that are passed on from parent
to offspring.
Learned behaviors: behaviors you have developed the ability
to do since your birth.
Trait: a feature passed from parents to offspring; sometimes
referred to as a characteristic
Dominant Gene: a gene for which the trait always appears
(dominates) when present.
Recessive Gene: a gene for which the trait usually only appears
when a dominant gene is not present.
EQ: What are learned behaviors?
EQ: How are inherited traits different from learned behaviors?
Getting You Thinking
How would you describe yourself? You might say you have blue eyes. You might
say that you like to play soccer. Many of the people in your family might also have
blue eyes, but not everyone can play soccer. Your eye color came from your
parents. However, your ability to play soccer was something you learned. Humans
and other animals are a mix of traits. from their parents and behaviors they learned
on their own.
Inherited Traits
An inherited trait is a physical characteristic that is passed from parents to their offspring. These characteristics include skin, eye,
and hair color. Additionally, these traits include your hair type, dimples and freckles, and a tendency to be short or tall.
Have you noticed how the people in some families tend to look a lot alike? They may have the same smile, nose, or hair color.
Even your ear lobes are an inherited trait (more info to come)! This is a trait that the people share. They inherited it from their
parents and grandparents.
Other animals have inherited traits, too, and so do plants. Gregor Mendel first discovered genetics by observing characteristics of
pea plants.
Inherited Behaviors
A behavior is a way of acting. Some
behaviors can be inherited, or they can be
learned. Inherited behaviors are called
instincts. These instincts are what help
many animals to survive.
For example:
-Birds heading south in the winter
-Bears hibernating in the winter
-Birds protecting their eggs
Learned Behaviors
Would you say you are better at using technology
than your parents or grandparents? If so, you learned how to
do this. This is not something you inherited from your parents.
Behaviors are learned each and every day. Some
behaviors may help us throughout our day. For example
making food, riding a bike, and using manners when speaking
with a neighbor. On the other hand, some behaviors do not
help us. They might include playing on the Wii or eating lots
of candy. Learned behaviors are things you have developed the
ability to do since your birth.
EQ: What is a gene?
EQ: How are traits passed on from parent to offspring?
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Genetic make-up
Heredity has influenced everyone’s life.
People might tell you that your hands are
just like your mother’s, you have your father’s
eyes, of that your facial features identify you
with one side of your family.
Other less visible characteristics (called traits)
include the greater chance of having certain
diseases, life expectancy, or some behavior
patterns. The total number of human traits is
unknown. There are more than five billion
people on Earth, and each one has a different
set of traits. You are really unique!
-Our cells are controlled by the
nucleus. The nucleus also contains
our genetic info on structures
called CHROMOSOMES
-Humans have 46 chromosomes
in each body cell, or 23 pairs.
Each parent contributes half of
each chromosome to pair to their
offspring.
-The chromosomes themselves
are made of thousands of genes.
-These genes are what provides
information on your specific
traits
Changing Genes
Genes are not only found in animals, but they are found in
plants. The genes control the size, shape, and color of
plants.
Scientists have been experimenting with ways to remove,
add, and change genes. By changing the genes in certain
plants, they have helped farmers grow better and faster
crops. They can even make the food item taste better.
Scientists have also found a way to help crops resist certain
insects.
Learning more about genes not only will help you
understand yourself, but can help make more efficient
plants and other products.
The foundation for research in the area of
heredity was set in the last part of the
nineteenth century by an Austrian monk
named Gregor Mendel. As he worked in the
monastery garden, helping to grow the
vegetables, he noticed that various garden
pea plants had differing traits, such as height
and blossom color.
Mendel conducted
experiments to change the
normal self-pollinating
pattern of the pea plant. He
cross-pollinated a purpleflowered plant with a whiteflowered plant, planted the
resulting seeds, and observed
the results.
By repeating his experiments
with other plants and then with
bees and mice, he made what
are considered major scientific
discoveries. He developed what is
often called Mendel’s first law,
the law of dominance and
recessiveness.
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The two letter combination of genes is known
as the GENOTYPE
 Example: B represents brown eyes and b
represents blue eyes
 If a child gets a dominant and recessive gene from
both parents the GENOTYPE would be Bb
 Since the B is a dominant trait it controls the trait;
therefore, the child will have brown eyes. The
specific trait is PHENOTYPE. The “PH”ysical
feature
Dominance means that in a
pair of genes, one tends to be
superior, or dominant, and
the other recessive. Long
stem length, purple flowers,
and rounded seeds are all
dominant traits with Mendel’s
pea plants.
- The genes themselves actually are in control for the different
traits (ex. A gene may control for eye color)
-All genes come in pairs
- There are different forms of genes called ALLELES. (ex. Brown
or blue eye color)
- Some genes are DOMINANT, or stronger and will appear more
often.
- Others are RECESSIVE, or weaker and will appear less often
-Dominant genes are ALWAYS represented by a capital letter.
-Recessive genes are ALWAYS represented by a lower case letter
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Most genes have two or more variations called
alleles.
 For example, the gene for hairline shape has two
alleles- widow’s peak or straight.
 An individual may inherit two identical or two
different alleles from their parents.
 When two different alleles are present they interact in
what is called a dominant or recessive manner
 If a dominant gene is present in genotype then the
person will take the dominant trait.
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Dominant and Recessive Traits in Humans
Dominant
Recessive
Brown eyes
Blue eyes
Curly hair
Straight hair
Freckles
No freckles
Detached earlobes
Attached earlobes
Dimples when you smile
No dimples when you smile
Can roll tongue into the shape of
aU
Can’t roll tongue into the shape
of a U
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Determine your own traits. Color them in
What are
our
traits?
Female: xx
Male: xy
Brown eyes: E
Not brown eyes: e
Tongue Roller: R
Not tongue roller: r
Tongue Flipper: F
Not tongue flipper: f
Attached Ear: a
Not attached: A
Widow’s peak: P
No widow’s peak: p
Not curly hair: h
Curly Hair: H
-Gwinnett County Online Campus (SOCC)
-The University of Utah: Learn.Genetics
-http://learn.genetics.utah.edu/
-National Genome Research Institute
-http://www.genome.gov/
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