+ results in a the exchange of the dominant and recessive alleles of the two genes

1. the frequency of recombination between two genes is a function of the physical distance between them

2. Recombination as measured by markers is reciprocal, ie both products of exchange occur with equal frequency. 

3. Recombinatino occurs at prophase 1 of meiosis when the homologues are synapsed together

4. any one combination occurs between 2 and 4 chromatids one each from a homologue but never between sister chromatids

5. two of four chromatids will be recombinant and two will be parental

5. recombination occurs at different places in different meiocytes.

Number of classes-1

describe the number of values in the final calculation of a statistic that are free to vary. 

Ex: there are four coat hooks on the wall. The first three people that come in have a freedom of choice, but the last one has only one hook to use. Therefore the degrees of freedom can be calculated : 4-1=3

pg. 41

if we were to reject "lack of linkage" in a Chi-square test, then we would accept "linkage" and could calculate the AB/ab test cross _______________

if double crossovers occured independently m it should be possible to predict the frequency of d.c.o. 

pg 43

first found in E. Coli

* requires the presence of F factor: F+ strains have the factor; F- do not. The F factor is a plasmid I.E  a circular piece of DNA separate from the main circular DNA. It contains ~ 100 genes. The genes function in (1) F factor DNA replication; 2. produce pili for cell capture; 3. transfer of DNA to the recipient and 4 occasional  recombination of F into host bacterial chromosome.

Figure 5.14 & 5.15

Hfr's can excise from the chromosome and take a chunk with it that will exist as a plasmid. IF the F mates with an F-, the transconjugants will carry the normal gene on the chromosome and another copy on the F factor. This configuration is called a merodiploid. 

(A + B)^n= a^2 + 2ab + b^2

n= number of additive alleles. in this case , a and b will both equal 1 because they represent the equal contributions of two alleles for each gene involved.

of the number of genes involved by determining the fraction of the F2 that overlaps the parentals on both sides of the cruve.

1 gene = 1/4

2 genes = 1/16 (1/4)^2

3 genes = 1/64 (1/4)^3

4 genes = 1/256 (1/4)4

the statistics of mean and variance (standard diviation) are useful in analyzing polygenic traits.

1. if the variance increases from f1 to f2, multiple genes are involved because mnay genotypes are produced that cause multiple phenotypes, which causes the variation to increase

2. the magnitude of increase give an indication of how many genes

sum of sample measurements/n

n = number in sample

frequency of all alleles at a locus. To calculate genotype frequency divide the three classes AA, Aa, aa by the total number in sample

AA= 90=.9

Aa=9=.09

aa=1=.01

1. a test of assumptions about a population

2. allows calculation of genotypic frequencies from allele frequencies (and vice versa)

for this relationship to hold the following must be true: 

1. organisms are diploid

2. reproduction is sexual

3. large population

4. random mating

5. no evolutionary forces; no mutation; no migration; no natural selection

measures natural selection

+the relative reproductive ability of a genotype. 

sickle cell anemia allelic frequency goes up to .20 despite detrimental effects. it involves a change in hemoglbin. Heterozygotes have resistance to malaria. the non-affected homozygotes are susceptible to malaria and thus have reduced fitness. 

effects of selection on allele frequencies (depending on the type of selection)

1. eliminate variation

2. maintain variation

3. change allele freq.

4. maintain allele freq.

5. create divergence between populations of a species

6. maintain iniformity

if migration continues, the allele frequencies between populations become BEEP

+increases the effective population sz and has the opposite effect of drift

will change genotypic frequencies without changing allele frequency in the absence of random selection.