Chap. 5 Genetics Linkage and Mapping in Eukaryotes

syntenic genes

genetics located on the same chromosome

cannot

linked genes

Syenthic genes r so close together that their alleles BLANK sort independently are r called BLANK genes

genetic linkage

BLANK an be quantified to map the positions of genes on chromosomes

recombinant chromosomes

alleles of syntenic genes can be reshuffled when crossing over occurs between homologs to produce BLANK

parental chromosomes or non-recombinant chromosomes

homologs that do not reshuffle alleles under study are called BLANK

genetic linkage mapping

BLANK plots the positions of genes on chromosomes

crossing over/recombination

BLANK can occur between sytenic genes is they r far apart on a chromosomes

syntenic genes

BLANK genes r close together and tend to segregate togther

BLANK genes r always syntenic and always located near one another

linked genes

genetic linkage

BLANK leads to the production of significantly more gametes with parental allele combinations than non parental combinations .

genetic linkage

BLANK can be recognized by comparing observed frequencies of gamete genotypes pr progeny phenotypes with those expected under independent assortment

Complete Gentic Linkage

BLANK is observed when no crossinf over occurs between linked genes, only parentaal gametes r formed

incomplete genetic linkage

when a mixture of parental and non parental gametes r formed

Recombination

BLANK frequency is a reflection of the physical distance between two genes

farther apart, closer together

crossing over occurs between genes at a higher rate when genes r BLANK and crossing over occurs between genes at a lower rate when genes r BLANK

two-point test-cross analysis

Morgan realized that linkage of autosomal genes in drosophila could be interpreting using a BLANK

Less than 50% of the time

Greater than 50% of the time

recombination occurs among linked genes less than BLANK percent of the time and greater then BLANK % of the gametes contain parental alleles combination

Centimorgan (cM)

a map unit is also called a BLANK

1% recombination

1 m.u. or 1cM Equals

more

When genes are linked there r BLANK parental phenotypes than recombinant phenotypes

the coefficient of coincidence (c)

observed double crossover/expected double crossers =

Interference

BLANK identifies the double crossovers expected but not produced

negative interference

BLANK interference has produced more double crossovers than predicted

less accurate

the farther apart linked genes are, the BLANK the recombination frequency reflects the real distance between them.

recombination frequency

species, age, environment, and sex may affect the BLANK

lower

the heterogametic sex usually has a BLANK recombination rate than the homogametic sex

natural selection

recombination is favored by BLANK

3.3 million

there r approximently BLANK SNPs in a human genome

SNP (single nucleotide polymorphisms)

most common type of genetic variation among individuals

Restriction endonucleases (enzymes)

RFLPs are changes in DNA sequence that r detected using DNA-cutting enzymes called BLANK

Restriction enzymes

BLANK recognize and cut specific sequeces of DNA

restriction fragments

pieces of DNA resulting from restriction enzyme cutting are called BLANK

Haplotype

the specific array of SNPs in a small region on a single chromosomes is called a BLANK

allelic phases

the arrangment of alleles of linked genes on parental chromosomes

linkage equilibrium

the genotype for a chromosome at one gene is expected to be independent of its genotype for other genes, this is called BLANK

linkage disequilibrium

when frequencies of certain haplotypes in a population deviate significantly from what is expected it is called BLANK