Transcript What is Genetics?

What is Genetics?
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Traits I have:
1. Widows peak or no widow peak
2. Eye Color
3. Hair color
4. Hair texture- wavy, straight, thick, thin
5. Hitch-hikers thumb or no hitch-hiker thumb
6. Left handed or right handed
7. Attached earlobe or dangle earlobe
8. Tongue roller or no tongue roller
9. Taste PTC paper or can not taste PTC
paper
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Write a paragraph describing yourself to a
pen pal who has never met you. Describe
yourself in a way that your pen pal will
recognize you. Use your physical traits to
describe you!
Genetics
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Is the study of how traits are inherited.
What are traits?
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Physical and non physical characteristics that
are pass down from the parents.
Examples:
Review
 Gene-
A
specific location
on a
chromosome
that controls a
trait.
GENE
Father of Genetics
Gregor Mendel
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Perform the 1st scientific study of how traits
are passed from one generation to the next.
Austrian monk born in 1822
Took over a garden plot in his monastery.
1856- began experimenting with garden
peas.
Was able to predict the outcome of the
offspring from the plants.
Peas do have traits!
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Mendel looked at 7 different traits in the pea
plant.
He died and was never famous until…
1900 three scientist rediscovered Mendel’s
work.
Types of traits
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Dominant- the trait that seems to cover up
another trait. (T)- Capital letter
Ex: Tongue roller is dominant
Recessive trait- the trait that was covered up
by the dominant trait or seemed to
disappear. (t)- Lower case letter
Traits
Terms to know:
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Purebred or Homozygous- organism that
always produces the same traits in its
offspring. (RR) or (rr)
Ex: Labrador retriever
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Hybrid or heterozygous- not pure.
(Rr)
Are we having fun yet?
What does the letters mean?
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The letters are called Alleles, they represent a trait.
For ex: Y= yellow, dominant
y= green, recessive
Must have two alleles to represent the trait passed
from each parent.
Capital letter always over-rides the lower case letter.
Genotype= letters (alleles)
Review
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Capital letter= dominant
Lowercase letter = recessive
YY- pure, homozygous and yellow
Yy- heterozygous and yellow
yy- homozygous and green
Practice
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If (T) = tall plant and (t) = short plant
Are these plants tall or short and are they
homozygous or heterozygous?
1. (Tt) = _______________
2. (tt)= ________________
3. (TT)= ______________
Genotypes= Alleles
Get a good look at SpongeBob,
What are some of his physical traits?
More practice
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Use the following table to write the physical
appearance of SpongeBob’s traits:
Trait
Dominant
Gene
Body Shape Squarepants
(S)
Body Color Yellow (Y)
Recessive
gene
Roundpants
(s)
Blue (y)
Eye Shape
Round (R)
Oval (r)
Nose Style
Long (L)
Stubby (l)
Write the physical trait that each group
of alleles represent.
1. LL = __________
2. yy= __________
3. Ss= __________
4. RR= __________
5. Rr= _____________
6. ll = _____________
7. Ss = ____________
8. Yy = ____________
1.
2.
3.
4.
5.
6.
7.
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Long nose
Blue body
Squarepants
Round eyes
Round eyes
Stubby nose
Squarepants
Yellow body
Which numbers have homozygous alleles?
Drawing time
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Draw SpongeBilly- he has the following
traits: (SS), (rr), (Ll), (YY)
More Drawing time
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Draw SpongeSalley, she has the following
traits: (ss), (yy), (Rr), (Ll)
What alleles would represent the
following physical traits?
a)
b)
c)
d)
e)
f)
g)
h)
Yellow body
Roundpants
Oval eyes
Long nose
Stubby nose
Round eyes
Squarepants
Blue body
a)
b)
c)
d)
e)
f)
g)
h)
YY or Yy
ss
rr
LL or Ll
ll
RR or Rr
SS or Ss
yy
Which numbers have a heterozygous set of alleles?