Python Notes for mca i year students osmania university.docx
Mendel punett squares2traitcrosses
1. Mendel & His Plants!
Gregor Mendel bred
pea plants and
recorded inheritance
patterns in the
offspring.
2. Mendel’s Experiment
Mendel bred true-breeding plants
When self-fertilized, a true-breeding plant
produces offspring identical in appearance
to itself generation after generation.
3. Mendel’s Experiment
Mendel crossed 2
plants- 1 true-breeding
for purple and 1 true-
breeding for white (P
generation)
Hegot the following
results: (F1
generation)
5. Step 2: Crossing the F1 generation
Onetrait is
dominant
Onetrait is
recessive
Ratio of Dominant :
recessive
12 purple: 4 white =
3 purple: 1 white
6. Interest Grabber continued
Section 11-1 Mendel’s Results
Parents (P) First Generation (F1) Second Generation (F2)
Long stems × short stems All long 787 long: 277 short
Red flowers × white flowers All red 705 red: 224 white
Green pods × yellow pods All green 428 green: 152 yellow
Round seeds × wrinkled seeds All round 5474 round: 1850 wrinkled
Yellow seeds × green seeds All yellow 6022 yellow: 2001 green
Go to
Section:
7. 1. In the first generation of each
experiment, how do the characteristics of
the offspring compare to the parents’
characteristics?
2. How do the characteristics of the
second generation compare to the
characteristics of the first generation?
8. Using Diagrams to show
inheritance: Punnett Squares
Alleles=
P P p p
alternativ
e forms of
genes
P = Pp P p
purple
p= white
P p P p
11. Rules for Punnett Squares
1. Draw a square
Place the traits for each parent across the top
and side (alleles)
Bring down the alleles from the top and across
from the side
Write the final ratio for the genotype &
phenotype
Add proper vocab terms
(homozygous/heterozygous AND Dom &
Recessive)
14. Inheritance & Probability
We have been examining inheritance using
probablilty
Probabilities predict AVERAGES! Not
individuals.
The offspring may not exactly match the
predicted outcome (the larger the sample, the
closer the expected values)
15. 25% WW (homozygous dominant)
25% ww (homozygous recessive)
50% Ww (heterozygous)
75% White
25% Black
Will it always turn out this way???
16. Two Factor/ Two Trait Crosses
Law of Segregation
Alleles
separate from one another during
meiosis
Law of Independent Assortment
Alleles
segregate independently of one
another (one does not depend on the other)
17. Two Trait Crosses
Separatethe alleles using the FOIL
method (kind of like a )
R rYy
RY Ry rY ry
RrYy x RrYy
20. Phenotypic Ratio
9 Yellow Round
3 Yellow wrinkled
3 green round
1 green wrinkled
ALLHeterozygote two-trait crosses will
result in a 9:3:3:1 ratio
22. A Few Different Types of
Inheritance
http://www2.edc.org/weblabs/incompletedom/incomp
23. A New Kind of Inheritance
Heterozygous
phenotype is a
blending of the
recessive and
dominant traits.
What kind of
inheritance?
Incomplete Dom.
24. Codominance
The dominant AND
the recessive are both
expressed
RR x rr
25. Multiple Alleles
Genes with more than two alleles.
Ex: Rabbits
C = full color; dominant to all other alleles
Cch = chinchilla, partial defect in
pigmentation, dominant to ch and c alleles
ch Himilayan, color on certain parts of the
body
c= albino, no color
27. Codominant Cross
Predictthe genotypic and phenotypic ratio
of a cross between a Full Color Rabbit
(Cch) and a himilayan (chc).
Genotype:25% Cch, 25%Cc, 25% chch, chc
Phenotype: 50% Full color, 50% himilayan
28. Sex-Linked Genes
Even the X and Y chromosomes code for traits
Since males only have one X chromosome, all traits are
expressed… even the recessive!
This explains why males are much more likely to develop
Colorblindness
Hemophilia
Duchenne Muscular Dystrophy
These are all genes on the X
chromosome!