Population-Scale Sequencing Data Enable Precise Estimates of Y-STR Mutation Rates

• NCJ Number: 250824
• Author(s): T. Willems, M. Gymrek, G. D. Poznik, C. Tyler-Smith, Y. Erlich
• Date Published: May 2016
• Length: 15 pages
• Agencies: NIJ-Sponsored
• Award: Robust STR calling from High-throughput Sequencing Technologies

Annotation

This project harnessed whole-genome sequencing data to estimate the mutation rates of Y chromosome STRs (Y-STRs) with 2–6 bp repeat units that are accessible to Illumina sequencing.

Abstract

Short tandem repeats (STRs) are mutation-prone loci that span nearly 1 percent of the human genome. Previous studies have estimated the mutation rates of highly polymorphic STRs by using capillary electrophoresis and pedigree-based designs. Although this work has provided insights into the mutational dynamics of highly mutable STRs, the mutation rates of most others remain unknown. The current project genotyped 4,500 Y-STRs by using data from the 1000 Genomes Project and the Simons Genome Diversity Project. Researchers then developed MUTEA, an algorithm that infers STR mutation rates from population-scale data by using a high-resolution SNP-based phylogeny. After extensive intrinsic and extrinsic validations, researchers harnessed MUTEA to derive mutation-rate estimates for 702 polymorphic STRs by tracing each locus over 222,000 meioses, resulting in the largest collection of Y-STR mutation rates to date. Using project estimates, researchers identified determinants of STR mutation rates and built a model to predict rates for STRs across the genome. These predictions indicate that the load of de novo STR mutations is at least 75 mutations per generation, rivaling the load of all other known variant types. Finally, researchers identified Y-STRs with potential applications in forensics and genetic genealogy, assessed the ability to differentiate between the Y chromosomes of father-son pairs, and imputed Y-STR genotypes. 250823 Understanding D isparities in service Seeking following forcible….Rape ANNO Since victims of drug-facilitated or alcohol-facilitated/incapacitated rape (DAFR/IR) are less likely than victims of forcible rape (FR) to seek medical or police assistance, the current study examined explanatory mechanisms in the pathway from rape type (FR vs. DAFR/IR) to disparities in post-rape service seeking (medical, rape crisis, criminal justice). ABST Participants were 445 adult women from a nationally representative household probability sample who had experienced FR, DAFR/IR, or both since age 14. Personal characteristics (age, race, income, prior rape history), rape characteristics (fear, injury, loss of consciousness), and post-rape acknowledgment, medical concerns, and service seeking were collected. An indirect effects model using bootstrapped standard errors was estimated to examine pathways from rape type to service seeking. DAFR/IR-only victims were less likely to seek services compared with FR victims despite similar post-rape medical concerns. FR victims were more likely to report fear during the rape and a prior rape history, and to acknowledge the incident as rape; each of these characteristics was positively associated with service seeking; however, only prior rape history and acknowledgment served as indirect paths to service seeking; acknowledgment was the strongest predictor of service seeking. Diminished acknowledgment of the incident as rape may be especially important to explaining why DAFR/IR victims are less likely than FR victims to seek services. Public service campaigns designed to increase awareness of rape definitions, particularly around DAFR/IR, are important to reducing disparities in rape-related service seeking. 34 references (Publisher abstract modified)