Summarizing Mapping Genomes

Summary

Genome mapping is similar to solving a big, complicated puzzle with pieces of information coming from laboratories all over the world. Genetic maps provide an outline for the location of genes within a genome, and they estimate the distance between genes and genetic markers on the basis of recombination frequencies during meiosis. Physical maps provide detailed information about the physical distance between the genes. The most detailed information is available through sequence mapping. Information from all mapping and sequencing sources is combined to study an entire genome.

Glossary

cytogenetic mapping

technique that uses a microscope to create a map from stained chromosomes

expressed sequence tag (EST)

short STS that is identified with cDNA

genetic map

outline of genes and their location on a chromosome

genetic marker

gene or sequence on a chromosome with a known location that is associated with a specific trait

genetic recombination

exchange of DNA between homologous pairs of chromosomes

genome mapping

process of finding the location of genes on each chromosome

cDNA library

collection of cloned cDNA sequences

genomic library

collection of cloned DNA which represents all of the sequences and fragments from a genome

genomics

study of entire genomes including the complete set of genes, their nucleotide sequence and organization, and their interactions within a species and with other species

linkage analysis

procedure that analyzes the recombination of genes to determine if they are linked

microsatellite polymorphism

variation between individuals in the sequence and number of repeats of microsatellite DNA

physical map

representation of the physical distance between genes or genetic markers

radiation hybrid mapping

information obtained by fragmenting the chromosome with x-rays

restriction fragment length polymorphism (RFLP)

variation between individuals in the length of DNA fragments generated by restriction endonucleases

sequence mapping

mapping information obtained after DNA sequencing

single nucleotide polymorphism (SNP)

variation between individuals in a single nucleotide

variable number of tandem repeats (VNTRs)

variation in the number of tandem repeats between individuals in the population