BIOLOGY 2C03 Lecture Notes - Lecture 7: Genetic Drift, Glutamine, Trinucleotide Repeat Disorder
Document Summary
Need high density maps: problem too few genes have been identified (phenotypically) to create a genetic map. Solution use a genetic locus other than a gene dna markers or nucleotide polymorphisms. Dna marker is locus with a known location that comes in identifiable variations (alleles) in a population. Nucleotide polymorphisms can be detected using molecular techniques. These allelic variations segregate according to mendelian principles and show linkage relationships. Polymorphism alternative forms of a genetic locus that differ in terms of nucleotide sequence. Locus a position on the length of dna and is not necessarily a gene: dna/molecular marker polymorphism useful for mapping, very common; members of a single species show enormous amounts of sequence variation. Alleles of dna markers are detected by molecular tools including pcr (polymerase chain reaction) or southern blot: refer to observations as molecular phenotypes. The frequency of dna polymorphisms in the human genome is high (1/350 base pairs, bp)
