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Genetics
Textbook: Biology11 Chapter 4
Heredity
Gregor Mendel
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Austrian monk (18221884)
Worked with pea plant
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Readily distinguishable
characteristics
Short generation time
Easy to control
pollination
Reproductive
structures of
flowers
http://anthro.palomar.edu/mendel/mendel_1.htm
transfer pollen from pollen
parent to seed parent
http://academic.kellogg.cc.mi.u
s/herbrandsonc/bio111/genetics
.htm
http://fig.cox.miami.edu/~
cmallery/150/mendel/here
dity.htm
Monohybrid Cross
Tall x Small (homozygous)
(p.3 and 132-137)
http://www.geneticfutures.com/thegift/info/sheet1.asp
The 3 Mendel’s laws (p.2)
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Mendel's first law (also called the law
of segregation) states that during the
formation of gametes (reproductive
cells), pairs of allele for a specific trait
separate so that offspring receive one
factor from each parent.
Mendel’s second law (p.6)
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Mendel's second law (also called the
law of independent assortment)
states that the distribution of alleles for
one trait that occurs during the
formation of gametes (meiosis) does
not affect the distribution of alleles for
other traits.
Mendel’s third law
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Mendel's third law (also called the law
of dominance) states that one of the
genes for a pair of inherited traits will
be dominant and the other recessive,
unless both factors are recessive.
Practice makes perfect
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Bio 11 p. 137 #1
And genetics worksheet 1
Test Cross:
To determine the
genotype of a dominant phenotype (p.4)
Practice makes perfect
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Do genetics worksheet 2
And p. 137-138 # 2 & 4
And p. 140 #5
Dihybrid Cross
And now, the fun part,
the F2 generation
Dihybrid cross
(answers for p.5 of booklet)
http://fig.cox.miami.edu/~cmallery/150/mendel/heredity.htm
Practice makes perfect
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Do genetics worksheet 3
Lab: Genetics of Corn
Lab: Virtual Fruit Fly
Multiple alleles (p.6)
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More than 2 alleles
Ex: eye colour of fruit flies
wild type(red) > apricot > honey > white
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Phenotype
wild type
apricot
honey
white
genotype
___
___
___
___
Multiple alleles (p.6)
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Exercice E1E4 x E2E3 (red x apricot)
Incomplete dominance
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(p.7, 144-145)
Ex: Colour of snapdragons’ flowers
Red x White
CRCR x CWCW (do Punnett square) Ratio F2?
Co-dominance (p.9)
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Another form of incomplete dominance.
Ex: red, white, roan cow, ABO blood groups
Alleles: IA, IA, i
Group A: antigen ___ : ____ or ____
Group B: antigen ___ : ____ or ____
Group AB: antigen ___ : ____
Group O: antigen ___ : ____
Co-dominance: try this
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Mother is A
Baby is AB
Man is O
Man is B
Who is the father? Show your answer
by drawing the 2 possible Punnett
Squares.
Practice makes perfect
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Do Genetics worksheet 4
Bio 11 p. 145 # 1 & 4.
Lethal genes (p. 9)
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Read and do Polygenic Inheritance
Polygenic Inheritance (p.9)
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Characteristic controlled by several pairs
of genes which are independent of each
other, often on different chromosomes
eg. Eye color, skin color, height
Shows continuous variation
Polygenic inheritance
AB
Ab
aB
ab
AB
AABB
AABb
AaBB
AaBb
Ab
AABb
AAbb
AaBb
Aabb
aB
AaBB
AaBb
aaBB
aaBb
ab
AaBb
Aabb
aaBb
aabb
Polygenic inheritance
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Let’s do bottom of p. 9 together
Polygenic Inheritance with
complimentary interaction (p.10)
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Pea comb = rrP_
Rose comb = R_pp
Walnut comb = R_P_
Single comb = rrpp
Let’s do p. 10 together
More practice
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Genetics worksheet 5
Linkage