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November 30, 2011
Classical / MendelianGenetics
Inheritance Patterns
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MendelRe-Enactment
Axial vs. TerminalFlowers
What will the genotypic & phenotypic ratios of the offspring be?
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What will the genotypic & phenotypic ratios of the offspring be?
What will the genotypic & phenotypic ratios of the offspring be?
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Complete practice examples #1-5 from your booklet pages 6 and 7
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Complete practice examples #6-9 from your booklet pages 7
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Complete practice examples #10-13 from your booklet page 8
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Complete practice examples #14-16 from your booklet page 9
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1 What will the phenotypic ratio of the F1 offspring be?
___ White: ___ Black
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2 What percentage of the F1 offspring would you expect to be white?
3 What will the genotypic ratios of the F1 generation be?
___ BB: ___ Bb: ___ bb
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4 Suppose a true-breeding right handed person and a true-breeding left handed person had children. What percentage of their children would be right handed?
5 Suppose two heterozygous individuals had children, what percentage of the offspring would be left handed?
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6 Suppose two heterozygous individuals had children. What percentage of the children would you expect to have the homozygous dominant?
7 A couple have 9 children. Of the 9 children, 7 can roll their tongues, and 2 can't. What are the possible genotypes of the parents? Choose all answers that are possible.
A Father: tt Mother: tt
B Father Tt Mother Tt
C Father TT Mother tt
D Father Tt Mother tt
Which is most likely?
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Testcross ExampleBlack wool is very brittle and is difficult to dye. A rancher an avoid getting black sheep in his flock by only breeding homozygous dominant sheep (WW). The rancher first has to determine if his white sheep are actually homozygous. Show how he could determine the unknown genotype of his white sheep by using a testcross.
Multiple Alleles ExampleYou are in the process of performing genetic experiments on flies in the lab when all of your flies escape. You manage to trap a couple of flies but you no longer know what genotype they are. One of the flies has red eyes, and the other has white eyes. You perform a testcross with the two and half of the resulting progeny have apricot eyes.
What was the genotype of your parent flye with red eyes?
Will any of your progeny have white eyes? Explain
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___ Red: ___ Pink: ___ White
8 There are two possible alleles for snapdragon colour, CR (red) and CW (white). These two alleles exhibit incomplete dominance and the phenotype of a heterozygous snapdragon (CRCW) is pink. If you were to cross a red snapdragon with a white snapdragon, what would be the colour distribution of the F2 generation?
Incomplete Dominance
Co-Dominance9 What percentage of the
offspring would you expect to be roan?
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Co-Dominance10 What percentage of the
offspring would you expect to be red?
Blood Type Example
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11 This couple can have children with which blood types? Choose all that are possible.
A A
B B
C AB
D O
12 Human blood type is determined by co-dominant alleles as well as dominant / recessive alleles. There are three different alleles known as IA, IB, and i. The IA and IB alleles are co-dominant, and the i allele is recessive. A woman with type A blood and a man with type B blood could potentially have offspring with which blood types?
A A
B B
C AB
D O
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Sex-Linked Examples
XRXr XRY
13 In cats an X-linked gene helps to determine colour. Homozygous R genotypes produce orange cats, homozygous r genotypes produce black cats, and heterozygotes are tortoise-shell colour. What percentage of the offspring from the following cross are expected to be orange?
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XrXr XRY
14 Females resulting from this cross will be:
A 50% black
B 100% black
C 50% orange
D 100% orange
E 50% tortoise shelled
F 100% tortoise shelled
Mendel's Law of Independent Assortment
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15 In pea plants, yellow seed colour is dominant to green seed colour and round seeds are dominant to wrinkled seeds. If a homozygous yellow-round seed is crossed with a homozygous green-wrinkled seed, what percentage of the F1 generation will be yellow and wrinkled?
X
16 If two of the F1 heterozygous plants (YyRr) from the previous question are crossed, what will the ratio of the F2 plants be?
X
YyRr YyRr
___ Yellow Round: ___ Yellow Winkled: ___ Green Round: ___ Green Wrinkled
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Feather colour in parakeets is controlled by two genes. For one pigment gene, the B allele produces blue colour, and the b allele does not produce any colour at all. For the other pigment gene, the Y allele produces yellow colour and the y allele does not produce any colour at all. Any genotype containing at least one B and one Y will produce a green parakeet.
1. Which of the following parental genotypes could produce offspring displaying all four different colour patterns?
a. BBYy x BbYyb. BbYY x Bbyyc. bbYY x bbyyd. Bbyy x bbYy
Feather colour in parakeets is controlled by two genes. For one pigment gene, the B allele produces blue colour, and the b allele does not produce any colour at all. For the other pigment gene, the Y allele produces yellow colour and the y allele does not produce any colour at all. Any genotype containing at least one B and one Y will produce a green parakeet.
2. What is the probability of obtaining a blue parakeet when two green heterozygous parakeets are crossed?
a. 0b. 3/16c. 1/4d. 9/16
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LinkedGenes
PowerPoint
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