Questions for you
Introductions to Genetics
Mendel and all that…
that…
Who Is This??
In your notes, answer these ?s:
• Who in your family do you most
look like?
like?
• In what ways do you NOT look
like that person?
• Who in your family has interests
and preferences most like
yours?
Mrs. Hunter’s relative….
Which
relative?
Yep, you guessed it…
It’
It’s Mrs. Hunter’
Hunter’s…….
…….
I. Some terms
A. Genetics =
study of heredity
Grandmother!
B. Heredity=
Heredity=
passing traits to offspring
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C. Traits
What traits do you share?
1. =
characteristics that parents can pass to
offspring
2. Examples of traits:
traits:
Eye color
Hair color
Shape of eyebrows
II. Gregor Mendel
(1822(1822-1884)
3. What traits do share with your
parents?
siblings?
cousins?
B. Mendel’
Mendel’s Work
1. Background
a. In peas, ♂ & ♀ parts are in every flower
b. Pollen = plant sperm
c. SelfSelf-pollination=
pollination= flower fertilizes itself
d. CrossCross-pollination=
pollination= flower fertilized by
another flower
A. Who was he?
z Austrian monk
z Studied the traits of pea
plants
z “Father”
Father” of modern
genetics
http://www.scienceshorts.com/gmendel.htm
1. Background
http://www.sciam.com/article.cfm?articleID=F4604E0F-E7F2-99DF-30C88C9489BD83A2
2. Mendel’s Experiments
a. Mendel controlled the pea pollination
b. ¿ How did he do this?
e. Peas have a lot of traits
f. Can’
Can’t study them all at once
g. Mendel studied one at a time
http://fig.cox.miami.edu/~cmallery/150/mendel/heredity.htm
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2. Mendel’s Experiments
2. Mendel’s Experiments
• Removed ♂ parts from a flower
• Dusted ♀ parts with pollen from another flower
• ¿ Was this self-pollination or cross-pollination?
cross-pollination
c. First Mendel crossed:
purebred
purebred
white flowered plant x purple flowered plant
(P1 generation)
(P1 generation)
all offspring were purple
(F1 generation)
2. Mendel’s Experiments
d. Then, he crossed the F1 generation
with itself (self(self-cross)
F1
X
F1
3 offspring were purple
1 was white
(F2 generation)
2. Mendel’s Experiments
e. What happened?
z Did
the traits blend?
z Why
were all the F1
flowers purple?
purple?
z Why
did we get 3 purple
& 1 white in F2?
http://www.biology.iupui.edu/biocourses/N100/images/heade
rnotes.gif
2. Mendel’s Experiments
f. Vocabulary we need:
z
Gene = part of a chromosome
that codes for a trait
or a protein
(we have two genes for
every trait)
z
Allele = a form of a gene
E.g.
white or
purple flowers
Vocabulary
z Dominant
= if present,
is always expressed
z Recessive
= both recessive alleles
must be present
for expression
http://www.healthsystem.virginia.edu/internet/huntdisease/geninfo.cfm
http://www.csulb.edu/~kmacd/361-6-Ch2.htm
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g. Back to Mendel
z
z
z
Let B = purple
Let b = white
P1 x P1
g. Back to Mendel
F1 x F1 (self(self-cross)
Bb x Bb
P1
BB
1 BB (purple)
2 Bb (purple)
1 bb (white)
bb
F1
Bb
3 purple
1 white
http://uz.wikipedia.org/wiki/Genetika
http://uz.wikipedia.org/wiki/Genetika
http://www.biology.iupui.edu/biocourses/N100/2k4ch10genetics.html
Questions
z Which
allele is dominant?
Purple flowers or white flowers?
z Did the alleles blend?
blend?
NO,
NO, flowers were either white or purple,
but not in between
z Why were all the F1 flowers purple?
purple?
purple is dominant
z Why did we get 3 purple & 1 white in F2?
purple is dominant
More Vocabulary
z Homozygous
=
2 of SAME alleles for
the same trait
(BB or bb)
z Heterozygous =
2 different alleles for
the same trait
(Bb)
Practice
z Copy
the table in the Quick Lab
on page 166 of the textbook
into your notes
z Circle your phenotype (physical appearance)
for each trait
z Count the # in class with each trait
z Write the numbers in the boxes
Questions
How many cleft chins: no clefts?
How many dimples: no dimples
3. How many hair above knuckles : hairless
fingers?
4. How many freckles: no freckles?
5. For which phenotypes do we know the
genotype (which genes are present)?
1.
2.
4
Bibliography
Graphics
1.
2.
Mendel picture http://www.scienceshorts.com/gmendel.htm 11/3/07
Garden pea picture http://www.sciam.com/article.cfm?articleID=F4604E0F-E7F2-99DF-30C88C9489BD83A2
11/3/07
3.
4.
5.
6.
7.
Pea characters http://fig.cox.miami.edu/~cmallery/150/mendel/heredity.htm 11/3/07
F1 cross http://www.biology.iupui.edu/biocourses/N100/2k4ch10genetics.html 11/3/07
Punnett Square http://uz.wikipedia.org/wiki/Genetika 11/3/07
Alleles http://www.csulb.edu/~kmacd/361http://www.csulb.edu/~kmacd/361-6-Ch2.htm 11/4/07
DNA, genes, chromosomes http://www.healthsystem.virginia.edu/internet/huntdisease/geninfo.cfm
http://www.healthsystem.virginia.edu/internet/huntdisease/geninfo.cfm 11/4/07
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