Lecture 3 Flashcards
What is positional cloning?
Positional cloning is a genetic technique used to identify the genetic basis of a particular phenotype or disease by mapping its location to a specific chromosomal region.
What are the steps involved in positional cloning?
The steps involved in positional cloning include identifying individuals or families with the phenotype of interest, mapping the phenotype to a specific chromosomal region using genetic markers.
What is the relationship between genes and recombination in positional cloning?
The closer two genes are, the more likely they will be inherited together (linkage). Genes that are further apart are likely to be affected by recombination.
What is the aim of genetic mapping?
The aim of genetic mapping is to determine how often the marker and the disease (or two markers) are separated by meiotic recombination.
What is a recombination fraction?
The recombination fraction is used to measure the rate of recombination between two loci / markers, and is a measurement of genetic distance.
What is a haplotype?
A haplotype is a block of loci that tend to be transmitted together through a pedigree.
What are DNA polymorphisms?
DNA polymorphisms are the basis of current genetic markers, examples include RFLPs, VNTRs, and SNPs.
What are RFLPs?
RFLPs (Restriction fragment length polymorphism) are genetic markers based on differences in the length of the sequence between two restriction cleavage sites.
What are VNTRs?
VNTRs (Variable Number of Tandem Repeats) are genetic markers where alleles often differ in the number of repeats, resulting in a high degree of polymorphism.
How are VNTRs different from RFLPs in terms of analysis?
VNTRs can be analyzed by PCR instead of Southern blotting, which is quicker and requires smaller quantities of DNA.
What are SNPs?
SNPs (Single-Nucleotide Polymorphisms) are genetic markers that involve any single base substitution.
What is the most common method used to confirm or refute linkage between two loci?
The LOD score is the most commonly used method to confirm or refute linkage between two loci.
What LOD score is generally accepted as evidence of linkage?
A LOD score of 3 or more is generally accepted as evidence of linkage.
