Term
| Wild Type Alleles (as opposed to Mutant Alleles) |
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Definition
| One that occurs frequently in nature and is usually, but not always, dominant |
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Definition
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Term
| Loss of function mutation |
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Definition
| Mutation that causes the reduction or loss of the specific wild-type function |
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Term
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Definition
| The resulting allele when the loss of function is complete |
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Term
| What influences phenotypic traits? |
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Definition
They can be influenced by more than one gene.
The allelic forms of each gene are also involved. |
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Term
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Definition
Neither trait is dominant
Offspring from a cross between parents with contrasting traits may have an intermediate phenotype
The phenotypic ratio is identical to the genotypic ratio in cases of incomplete dominance.
Threshold effect happens here |
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Term
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Definition
Part of incomplete dominance
Comes about if normal phenotypic expression occurs whenever a certain level (usually 50% or less) of gene product is attained. |
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Term
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Definition
Joint expression of two alleles of a gene is in a heterozygote results in phenotypic detection of both gene products.
No threshold effect here! |
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Term
| Studying multiple alleles (>2) |
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Definition
Multiple alleles can only be studied in populations, because any individual will have at most two alleles of the same gene.
Ex: ABO blood groups |
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Term
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Definition
Each individual is A, B, AB, or O phenotype
(Co)dominant: IA and IB alleles
Recessive: IO allele |
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Term
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Definition
| Responsible for an enzyme that can add the terminal sugar N-acetylgalactosamine (AcGalNH) to the H substance |
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Term
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Definition
| Responsible for a modified enzyme that cannot add N-acetylgalactosamine but instead can add a terminal galactose. |
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Term
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Definition
| Results from an absence of either terminal sugar |
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Term
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Definition
| A loss of function mutation can sometimes be tolerated in the heterozygous state - in this case the mutation would be recessive. If that recessive lethal allele is homozygous, the individual will not survive. |
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Term
| Recessive lethal allele that is dominant with respect to the phenotype |
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Definition
| When heterozygous, it can have a distinctive mutant phenotype. |
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Term
| Statistic problems with recessive lethal alleles |
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Definition
| When working with a population, you might not get the normal ratio of phenotypes or genotypes because part of the population will have died from the recessive lethal allele. |
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Term
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Definition
Homozygo AND heterozygote both will not survive. In order to pass them on, reproduction must happen before the individual dies.
Example: Huntington disease |
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Term
| When does Mendel's principle of independent assortment apply? |
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Definition
| When two modes of inheritance occur simultaneously, provided that the genes controlling each character are not linked on the same chromosome. |
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Term
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Definition
| The cellular function of numerous gene products contributes to the development of a common phenotype. |
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Term
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Definition
One gene masks the effect of another gene
Or
Two gene pairs complement each other such that one dominant allele is required at each locus to express a certain phenotype |
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Term
| How to predict epistasis based on ratios |
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Definition
| A ratio expressed in 16 parts (ex: 3:6:3:4) suggests that epistasis is occuring |
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Term
| What types of epistasis occur? |
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Definition
Recessive epistasis
Dominant epistasis
Complementary gene interaction |
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Term
| How does the Bombay phenotype for ABO blood groups relate to epistasis? |
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Definition
ABO blood groups are an example of epistasis.
The homozygous recessive condition at one locus masks the expression at a second locus. (H/h) |
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Term
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Definition
When expression of a single gene has multiple phenotypic effects, and it is quite common.
Ex: Marfan syndrome
Ex: porphyria variegata |
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Term
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Definition
| Genes present on the X chromosome exhibit unique patterns of inheritance due to the presence of only one X chromosome in males. |
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Term
| Lethal X-linked recessive disorders |
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Definition
Observed only in males
Females can be heterozygous carriers that do not develop the disorders. |
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Term
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Definition
The expression of a specific phenotype is absolutely limited to one sex.
Expression depends on hormones |
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Term
| Sex-influenced inheritance |
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Definition
The sex of an individual influences the expression of a phenotype that is not limited to one sex or the other
Expression depends on hormones |
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Term
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Definition
The percentage of individuals that show at least some degree of expression of the mutant genotype
(Does it exist?) |
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Term
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Definition
The range of expression of the mutant genotype
(To what extent does it exist?) |
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Term
| Two effects of the genetic background on suppression/expression |
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Definition
Genetic suppression occurs when other genes affect the phenotype produced by the gene in question.
The physical location of a gene may influence its expression due to a position effect. |
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Term
| Conditional or Temperature Sensitive Mutation |
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Definition
Mutations affected by temperature
These are useful in studying mutations that affect essential processes
Protein denaturation is involved in these mutations |
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Term
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Definition
Prevent the phenotype from reflecting the genotype.
Ex: include mutations in a biosynthetic pathway |
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Term
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Definition
Parental
Phenotypic expression may depend on the parental origin of the chromosome |
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Term
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Definition
| Occurs before or during gamete formation and may involve DNA methylation |
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Term
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Definition
| Add a methyl group to the nucleosomes. |
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Term
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Definition
Used to predict the frequency with which two independent events will occur simultaneously
If the alleles separate independently, you can treat them separately and multiply their probabilities. |
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Term
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Definition
Traits assort independently during gamete formation
All possible combinations of gametes will occur with equal frequency. |
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Term
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Definition
| Can be used with two independent traits |
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Term
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Definition
Involve three independent traits
Shows that Mendel's rules apply to any number of traits |
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Term
| Forked-line (branched diagram) method |
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Definition
| Easier to use than a Punnett square for analysis of inheritance of larger numbers of traits |
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Term
| Existing continuous variation hypothesis |
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Definition
Offspring were thought to be a blend of parental phenotypes.
Mendel suggested that heredity resulted in discontinuous variation, which opposed this theory. |
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Term
| Chromosomal Theory of Inheritance |
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Definition
| The separation of chromsomes during meiosis could be the basis for Mendel's principles of segregation and independent assortment. |
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Term
| What is a major consequence of independent assortment? |
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Definition
The production of dissimilar gametes.
Genetic variation results from independent assortment and it is very important to the process of evolution. |
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Term
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Definition
The probability of two independent events occurring at the same time
It is the probability of both events occurring (found via the product of the probability of each separately) |
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Term
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Definition
Calculate the probability of a generalized outcome that can be accomplished in more than one way.
States the probability of obtaining any single outcome, where that outcome can be achieved in two or more events, is equal to the sum of the individual probabilities of all such events |
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Term
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Definition
| The likelihood of a desired outcome when one event depends on another |
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Term
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Definition
Used to calculate the probability of any specific set of outcomes among a large number of potential events
Chance deviation from an expected outcome is diminished by larger sample |
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Term
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Definition
Used to test how well the data fit the null hypothesis
= SumOf [ (0-E)^2 / E ] |
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Term
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Definition
| Group A is no different from Group B |
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Term
| What does chi-square analysis require? |
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Definition
| The degree of freedom (df) needs to be taken into account, since more deviation is expected with a higher degree of freedom. |
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Term
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Definition
df = n - 1
n = number of categories |
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Term
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Definition
| Once the number of degrees of freedom is determined, the chi-square value can be interpreted in terms of a corresponding probability value (p). |
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Term
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Definition
A family tree with respect to a given trait.
Pedigree analysis reveals patterns of inheritance. |
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