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Intro to Genetics.notebook
January 18, 2017
DSW‐ What is Genetics?
1. How are traits inherited?
A: Traits of organisms are controlled by genes.
2. What was Mendel's role in the history of genetics?
A: He was the father of genetics.
3. Heredity and genetics help explain what?
A: They help to explain why people are different.
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Intro to Genetics.notebook
January 18, 2017
Intro to
Genetics
it's all in your genes
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Intro to Genetics.notebook
Studied math & science
January 18, 2017
What's up? I'm Gregor Mendel. Austrian monk
Tended the garden at the
monastery (church)
Experimented with pea plants to
find pattern of characteristics
passed to next generations.
"Father of Genetics"
What so special about pea plants??
1. grow and reproduce quickly 2. large variety of characteristics to study
3. can be crossed (bred) easily
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Intro to Genetics.notebook
January 18, 2017
What so special about pea plants??
1. grow and reproduce quickly 2. large variety of characteristics to study
3. can be crossed (bred) easily
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Intro to Genetics.notebook
January 18, 2017
Stamen
Mendel controlled the
process of pollination
by transferring pollen
Pistil
from the stamen of
one pea plant to the
pistil of another pea
plant.
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Intro to Genetics.notebook
January 18, 2017
Mendel's Experiment #1
X
short
short
True breeding = always produces offspring with same traits as parents.
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Intro to Genetics.notebook
January 18, 2017
Mendel's Experiment #2
X
tall
tall
Surprise!!!
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Intro to Genetics.notebook
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Mendel's Experiment #3
X
1st Filial Generation (F1)
tall
short
Parent Generation (P)
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Intro to Genetics.notebook
January 18, 2017
So what now??
2nd Filial Generation (F2)
1st Filial Generation (F1)
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Intro to Genetics.notebook
January 18, 2017
Mendel's Conclusion:
some plants contained factors for both tall & short. These factors are now known as genes. .
Genes are the units of heredity
Heredity: the passing of traits from parents to offspring
*traits are controlled by genes
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Intro to Genetics.notebook
January 18, 2017
Mendel kept careful, detailed records......
• some traits seemed to be "stronger" ‐ DOMINANT
• some traits seemed to be "weaker" than others ‐ recessive
DOMINANT GENES
(T)
every organism has 2
forms of a gene for each
trait
recessive genes
(t)
alleles
Ex: hairline (widow’s peak vs. straight)
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Intro to Genetics.notebook
January 18, 2017
Homozygous‐ (purebred) when an organism has 2 dominant or 2 recessive traits per gene (both capital or lowercase) Ex. TT, rr, SS
Heterozygous‐ (hybrid) when an organism has a combination of dominant and recessive traits per gene. (one capital & one lowercase)
Ex. Tt, Bb, Dd
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Intro to Genetics.notebook
January 18, 2017
• Genotype: genetic make‐up of an organism.
Ex: TT, Tt, tt
• Phenotype: physical expression of a particular genotype.
Ex: tall, short
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Intro to Genetics.notebook
January 18, 2017
Karl Correns‐ German botanist that found in some gene pairs, the genes are neither dominant or recessive. The traits appear "blended".
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Intro to Genetics.notebook
January 18, 2017
Incomplete Dominance
X
RR
WW
RW
notice anything weird??!?
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Intro to Genetics.notebook
January 18, 2017
6 Principles of Genetics
1. Traits, or characteristics, are passed on from one generation to the next.
2. Traits of organisms are controlled by genes.
3. Organisms inherit genes in pairs ­ one gene from each parent.
4. Some genes are DOMINANT and other are recessive .
5. Dominant genes hide recessive genes when both are inherited by an organism.
6. Some genes are neither dominant or recessive ­ Incomplete Dominance. 16
Intro to Genetics.notebook
January 18, 2017
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