Term
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Definition
| the simplest form of variation one might observe at a locus is a difference in the nucleotide present at a single nucleotide site |
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Term
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Definition
repeating sequences of 2-6 base pairs of DNA
*same as VNTRs* |
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Term
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Definition
the combination of alleles at multiple loci on the same chromosomal homolog
•Two homologous chromosomes that share the same allele (have same genotype) at each of the loci under consideration have the same haplotype
•These are most often used in population genetics for loci that are physically close
•The variable-nucleotides sites in a single gene can be used to define haplotypes for that gene
•This concept also works for larger regions when there is little or no recombination over the region |
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Term
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Definition
– shows the relationship among the haplotypes (individuals), placing each mutation on one of the branches
-if there is recombination (a crossover) in the haplotype, half of the haplotype might not match this haplotype anymore |
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Definition
| the sum total of all alleles in the breeding members of a population at a given time; a fundamental concept for the study of genetic variation in populations |
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Definition
| can use these frequencies in the gene pool to make predictions about the genotype frequencies in the next generation |
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Term
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Definition
– describes the relationship between allele and genotype frequencies – genetic variation is neither created nor destroyed by the process of transmitting genes from one generation to the next
•can be used to calculate genotype frequencies in the next generation from the allele frequencies in the current generation
•can also be used to calculate allele frequencies from the genotype frequencies within a single generation
-when doing chi-squared test: degrees of freedom = 1 |
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Term
| Assumptions of Hard-Weinberg |
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Definition
-Random mating
-All genotypes/alleles are viable
-Population must not be divided into subpopulations that are partially or fully genetically isolated
-Only applies to infinitely large populations |
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Term
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Definition
-allele frequency represented by length of VNTR
-this is looking at VNTR's someplace on the chromosome where you have a series of short tandem repeats -> you have primers that will amplify to either side of this DNA and make many different copies - length corresponds to how many number of repeats there are -> they have found 13 different loci VNTRs that are used for DNA fingerprinting
-do electrophoresis of the PCR products to find out the probability that an individual will have these alleles
-use Hardy Weinberg - 2pq |
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Term
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Definition
change in allele frequencies between generations due to sampling error
•p^2 → 0.5^2 → 0.25 → 25% of the time this population will “drift” away from the initial allele frequencies and become fixed for the A allele after just one generation
•Drift is a weaker force in larger populations
•Most new neutral mutations are lost from populations by drift
*this only occurs to neutral alleles*
-violates Hardy-Weinberg equilibrium |
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Term
| Fixation of an allele in a population |
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Definition
advantageous alleles can be brought to fixation or slightly deleterious alleles lost by the random process of drift
-The probability an allele becomes fixed in a population is equal to its frequency in the population (because everything is occurring at random – neutral)
-beneficial alleles become quickly fixed and negative alleles are lost quickly, where as neutral alleles are going to be subjected to drift, as they remain in the population |
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Term
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Definition
alleles that are equally likely to survive and reproduce
-alleles not affected by natural selection
-changes in allele frequency due to randomness
-over time will be fixed or extinct
-these alleles all have same chance at becoming fixed |
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Term
| Hardy-Weinberg equilibrium |
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Definition
– in large populations, genetic variation is neither created nor destroyed by the process of transmitting genes from one generation to the next
•If any alleles exist at a very low frequency, homozygous individuals will only very rarely be found
•Law still applies where there are more than two alleles per locus
•Applies to X-linked loci as well
•Use chi-square test to see if observed genotype frequencies at a locus fit this prediction/law |
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Term
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Definition
looking at the variation that exists in the population
-Not necessarily that is phenotypically expressed but it just exists in the population → gives information about the DNA |
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Definition
| typically looked at phenotype |
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Term
| places without recombination |
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Definition
mitochondria (From your mother)
-mitochondrial haplotypes can be used to trace human origins to Africa “Mitochondrial Eve”
•lots and lots of variation amongst individuals in Africa → meaning they have been there for a very long time
Y chromosome:
-These haplotypes also trace human origins to Africa “Eurasian Adam” |
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Term
| Probability that an allele gets fixed |
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Definition
1/(2N)
1 = new individual mutation
2 = total # of alleles in population
N = population size
*the higher N is, the more generations you need for fix/extinct* |
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