Chapter 7 Flashcards
linked genes
Genes located on the same chromosome.
linkage group
Genes located together on the same chromosome.
nonrecombinant (parental) gamete
Contains only the original combinations of genes present in the parents.
nonrecombinant (parental) progeny
Possesses the original combinations of traits possessed by the parents.
recombinant gamete
Possesses new combinations of genes.
recombinant progeny
Possesses new combinations of traits formed from recombinant gametes.
recombination frequency
Proportion of recombinant progeny produced in a cross.
genetic map
Map of the relative distances between genetic loci, markers, or other chromosome regions determined by rates of recombination; measured in percent recombination or map units.
coupling configuration
See cis configuration.
repulsion configuration
See trans configuration.
physical map
Map of physical distances between loci, genetic markers, or other chromosome segments; measured in base pairs.
map unit
Unit of measure for distances on a genetic map; 1 map unit equals 1% recombination.
centiMorgan (cM)
Another name for map unit.
two point test cross
Cross between an individual heterozygous at two loci and an individual homozygous for recessive alleles at those loci.
three point test cross
Cross between an individual heterozygous at three loci and an individual homozygous for recessive alleles at those loci.
interference
Degree to which one crossover interferes with additional crossovers.
coefficient of coincidence
Ratio of observed double crossovers to expected double crossovers.
mapping function
Relates recombination frequencies to actual physical distances between genes.
lod (logarithm of odds score)
Logarithm of the ratio of the probability of obtaining a set of observations, assuming a specified degree of linkage, to the probability of obtaining the same set of observations with independent assortment; used to assess the likelihood of linkage between genes from pedigree data.
genetic marker
Any gene or DNA sequence used to identify a location on a genetic or physical map.
linkage analysis
Gene mapping based on the detection of physical linkage between genes, as measured by the rate of recombination, in progeny from a cross.
genome-wide association studies
Studies that look for nonrandom associations between the presence of a trait and alleles at many different loci scattered across a genome—that is, for associations between traits and particular suites of alleles in a population.
haplotype
A specific set of linked genetic variants or alleles on a single chromosome or on part of a chromosome.
linkage disequilibrium
Nonrandom association between genetic variants within a haplotype.
single nucleotide polymorphism (SNP)
Single-base-pair differences in DNA sequence between individual members of a species.
somatic-cell hybridization
Fusion of different cell types.
cell line
Genetically identical cells that divide indefinitely and can be cultured in the laboratory.
heterokaryon
Cell possessing two nuclei derived from different cells through cell fusion.
deletion mapping
Technique for determining the chromsomal location of a gene by studying the association of its phenotype or product with particular chromosome deletions.
