Microsatellite Mutations and Inferences About Human Demography Microsatellites

Microsatellite Mutations and Inferences About Human Demography ØMicrosatellites and their characteristics; Ø The application of microsatellites, including human demography inference. BI 820 3/23/04

Microsatellites and their characteristics 1. Microsatellites are tandemly repeated DNA motifs of 1– 6 bp in length dispersed throughout the whole genome; (AT)5, (AT)6, (AT)3…. (ACT)1, (ACT)8, (ACT)3…. 2. Microsatellites occur at a high frequency in all examined eukaryotes and at a lower frequency in prokaryotic genomes; 3. Microsatellite loci increase and decrease in length due to polymerase slippage during DNA replication and recombination, both of which are consequences of having a series of identical tandemly repeated units. 4. Microsatellite loci are highly variable, even in organisms that display little genetic variation 5. Microsatellites are informative 6. Microsatellites are relatively straightforward to identify (AT)5 (AT)7 (AT)10 PCR

The applications of microsatellites 1. Originally used for family study; 2. Today applications include genetic mapping, forensics, studies of human genetic disease proliferation and assessments of genetic diversity 3. Microsatellites are not preferred for genetic analysis; Microsatellites have high mutation frequency, and have the ability to both gain or lose repeat unit. ---->The infinite site assumption is no long true for microsatellite analysis. (AT)5 -->(AT)7 X (AT)7 X X(AT)8 -->(AT)7 4. However, based on some statistical analysis of microsatellites, population expansion is still observed in different subpopulations.