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26 Cards in this Set
- Front
- Back
prediction if homunculus hypothesis correct?
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all progeny will look like one parent
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prediction if blending hypothesis correct?
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all progeny will appear like mix of parents
recessive parental trait will not re-appear in F2 |
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alleles
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different copies of genes
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pure-breeding lines
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families of organisms that produce offspring with specific parental traits that remain constant from generation to generation
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segregation
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equal separation of alleles for each trait during gamete formation, in which one allele of each gene goes to each gamete
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mono-hybrid cross
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crosses between parents that differ in only one trait
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heterozygote
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individual with two different alleles for a given gene or locus
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homozygote
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individual with identical alleles for a given gene or locus
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test cross
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a cross used to determine the genotype of an individual showing a dominant phenotype by mating with an individual showing the recessive phenotype
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What is the genotype of a plant that produces yellow peas?
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Y/-
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What genotype can you cross with a Y/- plant with to help you
distinguish the correct genotype? |
y/y
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independent assortment
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alleles of one gene separate into gametes randomly with respect to alleles of other genes
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segregation
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the separation of the two alleles of a gene into different gametes
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Di-hybrid cross
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cross in which two traits are segregating
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Law of the product
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probability of 2 or more independent
events occurring together is the product of the probabilities that each event will occur by itself. |
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Law of the sum
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probability of two or more mutually
exclusive events occurring is the sum of their individual probabilities |
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What is the probability that the progeny of the R/r x R/r cross
will be wrinkled? |
probability that one parent will contribute r allele
X probability that the other parent will contribute the r allele 1/2 X 1/2 = 1/4 |
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What is the probability that the progeny of the R/r x R/r cross
will be heterozygous? |
probability that one parent will contribute a dominant allele
X probability that the other parent will contribute the recessive allele (1/2 X 1/2) + (1/2 X1/2) = 2/4 = 1/2 |
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Affected children have at least one affected parent
Two affected parents can produce unaffected children, if both parents are heterozygotes |
Dominant Traits: “Vertical” Pattern of Inheritance
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Affected children can be the children of two unaffected parents.
All of the children of two affected parents should be affected. |
Recessive traits: “Horizontal” patterns of inheritance
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If the recessive trait is common, the patterns of inheritance
may show a ______ pattern of inheritance (eg. sickle cell anemia among African-Americans). |
If the recessive trait is common, the patterns of inheritance
may show a vertical pattern of inheritance (eg. sickle cell anemia among African-Americans). |
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A 1:2:1 ratio might imply:
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incomplete dominance
or codominance |
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Incomplete dominance
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phenotype of heterozygote is
intermediate between the phenotypes of the two homozygote parents (often due to reduced gene dosage) |
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Co-dominance
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phenotype of the heterozygote looks like
both homozygote parents |
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haploinsufficicency
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a rare form of dominance in which an individual heterozygous for a wild=type allele and a null allele shows an abnormal phenotype because the level of gene activity is not enough to produce a normal phenotype
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null allele
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mutations that abolish the function of a protein encoded by the wild-type allele. Such mutations either prevent synthesis of the protein or promote synthesis of a protein incapable of carrying out any function
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