Chapter 5 Flashcards
in some fungi, the haploid cells that result from meiosis. also known as haplospores
ascospores
saclike structure in some varieties of fungi that houses all four haploid products of meiosis.
ascus
a unit of measure of recombination frequency. One cM is equal to a 15 chance that a marker will be separated from a marker at a second locus due to crossing-over in a single generation.
centimorgan/cM
observable regions in which nonsister chromatids of homologous chromosomes cross over.
chiasmata
a statistical test to determine the probability that an observed deviation from an expected outcome occurs solely by chance.
chi-square test
the phenomenon of crossovers not occurring independently
chromosomal interference
the ratio between the actual frequency of double crossovers observed in an experiment and the number of double crossovers expected on the basis of independent probabilities.
coefficient of coincidence
a tetrad in which the arrangement of ascospores indicates that the two alleles of a gene segregated from each other in the first meiotic division.
first-division segregation pattern
the proximity of two or more markers on a chromosome; the closer together the markers are, the lower the probability that they will be separated by recombination. Genes are linked when the frequency of parental type progeny exceeds that of recombinant progeny.
genetic linkage
group of genes chained together by linkage relationships.
linkage group
described genes whose alleles are inherited together more often than not; linked genes are usually located close together on the same chromosome.
linked
a designated location on a chromosome. See alpha-globin locus and beta-globin locus.
locus
synonymous with centimorgan.
map unit/m.u.
mathematical equation that compensates for the inaccuracies inherent in relating recombination frequencies to physical distance.
mapping functions
the process of determining the locus of a gene on a particular chromosome
mapping
