Mendelian exceptions 11 3
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Transcript of Mendelian exceptions 11 3
Mendelian ExceptionsMendelian Exceptions
Chapter 11Chapter 11
Section 3Section 3
Mendel’s Principles Revisited
Inheritance of biological _____________ is determined by individual units known as ______.
During sexual reproduction, genes are passed from parents to _________.
Two or more forms of the gene for a single _____ exist, some forms of the gene may be _________ and others may be recessive.
characteristicscharacteristics
offspringoffspring
genesgenes
traittraitdominantdominant
Mendel’s Principles Revisited
Organisms typically have ____copies of each gene, (one from each _______)
An organism’s _____ of genes (2 alleles) are segregated from each other when ________ are formed.
Alleles for different ______ usually segregate _____________ of one another. (through meiosis)
(Law of Independent Assortment)(Law of Independent Assortment)
independentlyindependently
parentparenttwotwo
gametesgametes
genesgenes
pairpair
Independent Assortment in Peas
__ Round yellow__ Round green__ Wrinkled yellow__ Wrinkled green
99333311
Incomplete Dominance
In incomplete dominance, neither allele is __________ so there is a blending of ______ when two different alleles for the same trait occur together.
Colors blendblend together (______________
individuals = 3rd phenotype)
dominantdominanttraitstraits
heterozygousheterozygous
red whitepink
Incomplete Dominance
In Four O’ Clocks, if you cross a red _____(which is always pure) with a white _____ (that is also always pure) , you get apink _____ (whichis always hybrid /heterozygous
RRRRWWWW
RWRW
RWRW
RW RW
Incomplete Dominance
In another flower, if red ____ and blue ____ flowers are crossed, they produce a 3rd purple ____ flower
What would be the genotype ratio and phenotype ratio if you crossed two purple flowers?
RRRRBBBB
RBRB
Incomplete Dominance Cross of two purple flowers
____ X ____ What are gamete possibilities? genotype ratio
1RR : 2RB : 1BB1RR : 2RB : 1BB phenotype ratio
1red : 2 purple : 1 blue1red : 2 purple : 1 blue Can you have a
heterozygous red orhybrid blue flower? ___
B
R
R B
BBRB
RR RBred purple
purple blue
RBRB RBRB
nono
Codominance Both _______ contribute to the phenotype
of the organism by showing up simultaneously (at the same time) in heterozygous
individuals. In cattle and horses, if you cross
a pure ____ (RR) with a pure ______ (WW), you get (RW) which produces the color _____.
allelesalleles
redredwhitewhite
roanroan
Codominance
These cattle or horses actually have both red and white hairs intermixed, or are spotted. Roan is a third ___________.
If you cross a roan with a white…
W
W
R W
WWRW
RW WW
phenotypephenotype
roan
roan
white
white
Codominance Andalusian chickens also show this
pattern of inheritance. If you cross a black (BB) chicken With a white (WW) chicken You get black+white speckled (BW) chicken
Multiple Alleles
In this pattern of inheritance, the genes have more than _____ alleles controlling them and are therefore said to have multiple alleles. No individual has more than _____ alleles, but there are more than _____ possible alleles in a population, so a ______ will be expressed in more than two forms.
twotwo
twotwotwotwo
traittrait
Multiple Alleles
Blood type in humans is an example of this inheritance pattern.
The ______ different blood groups:
A, B, O, and AB Are produced
by ______ different alleles:
A, B, and O
fourfour
threethree
Phenotype Genotype
A AA or AO
B BB or BO
AB AB only
O OO only
Multiple Alleles Examples of Blood type crosses
Phenotype(Blood Type
Multiple Alleles
Genotype
Blood Groups
Antigen on Red Blood Cell
Safe Transfusions
To From
Multiple Alleles
The example of _______ hair color, which has at least four different alleles, (on text pg 273) is seen in these different Rex rabbits.
rabbitrabbit
Polygenic Traits
Traits controlled by two or more genes Show a wide range of phenotypes The phenotype
is produced by the interaction of more than ________ of genes.
1 pair1 pair
Polygenic Traits These are called ___________ traits,
which means “having _______ genes”. In humans, _____ color, _____ color,
polygenicpolygenicmanymany
skinskineyeeye
Polygenic Traits These are called ___________ traits,
which means “having _______ genes”. In humans, _____ color, _____ color, and _____ color
polygenicpolygenicmanymany
skinskineyeeye
hairhair
Polygenic Traits These are called ___________ traits,
which means “having _______ genes”. In humans, _____ color, _____ color, and _____ color are just a few of
the many traits __________ by many genes.
polygenicpolygenicmanymany
skinskin
controlledcontrolled
eyeeye
hairhair
Polygenic Traits Sometimes the combination of the
different genes results in continuous __________ of these traits.
The combined size of all the ______ parts from head to foot, determines the _______ of the person.
variationvariation
bodybody
heightheight
James Bond Height Chart