Transcript Unit 10 Heredity PPT from Class

Unit 12 - Heredity
Unit 12 - Heredity
father of genetics
Gregor Mendel
was born in 1822
in Heinzendorf,
Austria, to a
peasant farming
family.
Austria
Poland
Italy
Germany
Czech Republic
Austria
When he was 21, one of Mendel’s teachers
took note of his exceptionally bright mind and
persuaded him to join the Augustinian monks.
St.Thomas Church,
(now Brno, Czechoslovakia)
Mendel conducted
numerous experiments on
plants. Mendel narrowed
his focus to one particular
type of garden pea.
For 8 years, Mendel
experimented with over
28,000 peas in the large
gardens attached to the
monastery.
Rather than study
every characteristic
of the garden pea,
Mendel narrowed his
observations to 7
traits
Garden Pea Traits
Observed
Seed shape
smooth
wrinkled
Seed color
yellow
green
Pod shape
smooth
Pod color
green
Flower color
purple
Flower location Along stem
Plant size
tall
bumpy
yellow
white
at tip
short
In 1866 when Mendel was 44, his
experimental results were published
. . . and ignored long after he died.
In 1900, 3 scientists Carl Correns, Hugo de Vries, and
Erich von Tschermak all independently rediscovered and
verified Mendel's principles, marking
the beginning of modern genetics.
He is now considered the father of
genetics.
Genetics & Heredity
Heredity-The passing of
characteristics from parents
to offspring
Genetics -The branch of
biology that focuses on
heredity
Are these inherited traits?
Your eye color
Your hair color and texture
Your height
Are these inherited traits?
Your personality
Your musical,
athletic, and
artistic abilities
Think about this….
•My parents have brown eyes, why
are mine blue?”
•“My brother is tall. Why am I
short?”
•“Why does my sister have blonde
hair while mine is brown?”
Mendel’s studies led to…
•Alleles- the different versions of a
gene (an individual receives one allele
from each parent)
Mendel’s studies led to…
•Dominant- the expressed form of the trait
ex. H
•Recessive- the trait that is not expressed if a
dominant allele is present
ex. h
Mendel’s studies led to…
•Genotype- the genetic makeup of
an organism (the set of alleles an
individual has)
ex: Ff or FF
•Phenotype- the physical
appearance of an organism
ex. has freckles
Mendel’s studies led to…
•Homozygous- the two alleles
present for a characteristic are the
same
Ex: hh or HH
•Heterozygous- the two alleles
present for a characteristic are
different
Ex: Hh
Tongue Roller
R = Tongue Roller
r = Unable to Roll Tongue
Widow’s Peak
W = Widows Peak
w = Lack of Widow’s Peak
Free Ear Lobe
Attached Ear Lobe
E = Free Ear Lobe
e = Attached Ear Lobe
Hitchhiker’s Thumb
H = Straight Thumb
h = Hitchhiker’s Thumb
Bent Little Finger
B = Bent Little Finger
b = Straight Little Finger
Mid-digital Hair
M = Mid-Digital Hair
m = Absence of Mid-Digital Hair
Dimples
D = Dimples
d = Absence of Dimples
Short Hallux
H = Short Hallux
h = Long Hallux
Short Index Finger
S = Short Index Finger
s = Long Index Finger
The Theory of Heredity
Inherited allele
for purple P
Inherited allele
for purple P
HOMOZYGOUS purple flower (PP)
The Theory of Heredity
Inherited allele
for purple P
Inherited allele
for pink flower (p)
HETEROZYGOUS purple flower (Pp)
The Theory of Heredity
Inherited allele
for pink flower (p)
Inherited allele
for pink flower (p)
HOMOZYGOUS pink flower (pp)
PREDICTING HEREDITY
Probability
• The likelihood that a specific event will occur
• Probability = # of 1 kind of possible outcome
Total number of possible outcomes
• Example: What is the probability that a tossed
coin will be heads?
• ½ or 50%
Probability
• What is the probability that a couple will
have four boys?
½ x ½ x ½ x ½ = 1/16
• What is the probability you will win the
lottery?
6/50 x 5/49 x 4/48 x 3/47 x 2/46 x 1/45…
Monohybrid Cross:
a cross that shows the possible offspring for one trait
A
a
A
AA
Aa
a
Aa
aa
Aa x Aa
A: White fur
a: Brown fur
Genotypic Ratio: 1:2:1
Phenotype: 3 white:1 brown
Dragons have either smooth or wrinkled
noses. Wrinkled is dominant over smooth. If a
smooth-nosed female dragon is crossed with a
heterozygous wrinkle-nosed male, how many
of their offspring are likely to have smooth
noses?
_
_
*genotypic ratio:
*phenotypic ratio:
*What is the probability of
having smooth-nosed
offspring?
*What is the probability of
having two smooth-nosed
offspring?
_
_
Dihybrid Cross:
a cross that shows the possible
offspring for two traits
Fur Color:
B: Black
b: White
Coat Texture:
R: Rough
r: Smooth
BbRr x BbRr
Dihybrid Cross:
BbRr x BbRr
First, you must find ALL possible gametes that
can be made from each parent.
Remember, each gamete must have one B and
one R.
Dihybrid Crosses:
a cross that shows the possible offspring for two traits
Fur Color:
B: Black
b: White
Coat Texture:
R: Rough
r: Smooth
BbRr x BbRr
Phenotypic Ratio:
9:3:3:1
BR
Br
bR
br
BR
BBRR
BBRr
BbRR
BbRr
Br
BBRr
BBrr
BbRr
Bbrr
bR
BbRR
BbRr
bbRR
bbRr
br
BbRr
Bbrr
bbRr
bbrr
Dihybrid Crosses:
a cross that shows the possible offspring for two traits
•How many of the
offspring would have
black, rough coat?
•How many of the
offspring would have
a white, smooth
coat?
BR
Br
bR
br
BR BBRR
BBRr
BbRR
BbRr
Br
BBRr
BBrr
BbRr
Bbrr
bR
BbRR
BbRr
bbRR
bbRr
1
16
•How many of the
offspring would have
a white, rough coat?
br
BbRr
Bbrr
bbRr
bbrr
More Complex Patterns
of Heredity
1
–Codominance
–Multiple Alleles
–Sex-Linked Traits
16
Codominance:
two dominant alleles are expressed at
the same time
1
CRCR
CWCW
16
CRCW
Codominance
• Sickle-Cell
Anemia is another
codominant trait.
NS
1
NA
NA
NSNA
NSNA
NA=Normal RBC
16
NS=Sickle
Cell RBC
NA
NANA
NANA
Pedigree Analysis
Pedigree
Used to show genetic
inheritance over
generations in a family
Pedigree Example
male
Marriage
female
Female
Carrier
Offspring
Royal Family Hemophilia
People who are “carriers” for
People
affected
the disease,
butbydothe
notdisease
have
symptoms—can pass on to
children