Skip to main content
Premium Trial:

Request an Annual Quote

New Algorithm Detects Duplicate DNA and Copycat Genes--Five Percent of Human Genome is Copied

NEW YORK, Aug. 9 - The human genome is littered with spare parts, according to a new analysis by geneticists from Case Western Reserve University and Celera Genomics.


Genetic scientists have long known about gene-segment duplication, the process by which copied shards of DNA break off and wander into a new position in the genome. Sometimes, disease is the result. More often, the replica genes cause no immediate harm, and eventually wind up modified by evolution or "silenced" altogether.


This biological phenomenon has been a major frustration for gene sequencers, since the assembly programs designed to match overlapping fragments of DNA are easily confused by the thousands of duplicate or near-duplicate segments that lurk in the human genome.


To solve this problem, the Case Western team, led by Jeff Bailey and Evan Eichler, devised an algorithm to pinpoint these copies in Celera's whole genome-shotgun data.


They identified nearly 9,000 segments of duplicated DNA, ranging from tens to hundreds of kilobases. By this calculation, copies account for at least 5 percent of the human genome.


The group also identified 169 regions of "genomic instability," areas where duplication-based rearrangement seems to happen more readily and may be prime locations for genetic disease.


Another surprising discovery: Because duplicate sequences are so common, the team estimates that as many as 100,000 of the SNPs in the public database are probably misidentified, the result of variant sequences rather than true polymorphisms.


Evolutionary biologists will undoubtedly be interested in these findings, since against all expectations, many of the duplicated DNA segments in the human genome seem to be particularly dense with genes. One theory holds that this process is one of the major engines of evolution--these "extra" gene segments, biologically superfluous, can be modified or specialized through mutation with less likelihood of causing harm.


The research appears in the Aug. 9 Science.

The Scan

Study Points to Tuberculosis Protection by Gaucher Disease Mutation

A mutation linked to Gaucher disease in the Ashkenazi Jewish population appears to boost Mycobacterium tuberculosis resistance in a zebrafish model of the lysosomal storage condition, a new PNAS study finds.

SpliceVault Portal Provides Look at RNA Splicing Changes Linked to Genetic Variants

The portal, described in Nature Genetics, houses variant-related messenger RNA splicing insights drawn from RNA sequencing data in nearly 335,700 samples — a set known as the 300K-RNA resource.

Automated Sequencing Pipeline Appears to Allow Rapid SARS-CoV-2 Lineage Detection in Nevada Study

Researchers in the Journal of Molecular Diagnostics describe and assess a Clear Labs Dx automated workflow, sequencing, and bioinformatic analysis method for quickly identifying SARS-CoV-2 lineages.

UK Team Presents Genetic, Epigenetic Sequencing Method

Using enzymatic DNA preparation steps, researchers in Nature Biotechnology develop a strategy for sequencing DNA, along with 5-methylcytosine and 5-hydroxymethylcytosine, on existing sequencers.