Mutation Rate at Commonly Used Forensic STR Loci: Paternity Testing Experience

Faruk Aşıcıoğlua,Fatma Oguz-Savran,Ugur Ozbek

doi:10.1155/2004/643086

Faruk Aşıcıoğlua, Fatma Oguz-Savran + Show 1 more

Open Access

https://doi.org/10.1155/2004/643086

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Abstract

Paternity tests are carried out by the analysis of hypervariable short tandem repeat DNA loci. These microsatellite sequences mutate at a higher rate than that of bulk DNA. The occurrence of germline mutations at STR loci posses problems in interpretation of resulting genetic profiles. We recently analyzed 59–159 parent/child allele transfers at 13 microsatellite loci. We identified 12 mutations in 7 microsatellite loci. No mutations were occurred in other 6 loci. The highest mutation rate was observed with 5 mutations at D8S1179 locus at different alleles. The event was always single repeat related. The mutation rate was between 0 and 1.5 x 10-2 per locus per gamete per generation. The mutation event is very crucial for forensic DNA testing and accumulation of STR mutation data is extremely important for genetic profile interpretation.

Highlights

Microsatellites are tandem repeats of short units of DNA that occur with high frequency throughout the genomes of many organisms [7]
We identified 12 mutations in 7 microsatellite loci in a total of 3248 paternal alleles and in 1 locus in a total of 3240 maternal allele transfers (Table 1)
In each family with a mutation, we calculated the power of evidence for parenthood by using the other genotyped loci data, this was from 99.99% to over 99.999%

Summary

Introduction

Microsatellites are tandem repeats of short units of DNA that occur with high frequency throughout the genomes of many organisms [7]. Microsatellite loci have a high degree of variability that is caused by a high rate of mutations that alter microsatellite length [5]. Renewed replication in this misaligned state leads to insertion or deletion of repeat units, altering allele length. General estimates of STR mutational rates have been shown to depend on the consensus repeat length.

Results

Conclusion