Thermo ebook on eQTL - 3

A Deeper Understanding of Your
GWAS Results
A combination of genomics and transcriptomics delivers eQTLs-
potential biomarkers for traits identified in GWAS.
Mike May, Ph.D.
RNA level (results from eQTL studies)-can reveal
the function of the SNP in the trait.

In 1958, the late Francis Crick proposed the central
dogma of biology, and scientists have been chasing
connections between genotype and phenotype ever
since. The human genome contains tens of millions
of single nucleotide polymorphisms (SNPs), but only
about 2,000 of those in any one person can be linked
to a phenotype-a trait or disease1-because most
of those variants lie in noncoding regions of DNA.
Still, scientists can explore those connections further
with expression quantitative trait loci (eQTLs).

The overall point of exploring eQTLs is that their
impact on the expression of a gene can affect the
linked phenotype or trait. In particular, eQTL analysis can be used to better understand the cause of a
disease as well as its progression and potential treatments. Going from a potential link to a validated
one, though, gets complicated and expensive-unless the scientist uses the best tools.

In brief, eQTLs are genetic variants that alter expression levels of genes. eQTLs are identified from a
co-analysis of genotype (DNA) and gene expression
levels (RNA) in a set of samples. eQTLs are important since they can enhance our understanding of results from genome-wide association studies (GWAS).
In such studies, most of the identified variants-
single-nucleotide polymorphisms (SNPs)-exist
outside of coding regions of DNA; these variants
probably play a role in regulating gene expression.
To assess that role, scientists compare the variants
found with GWAS to results from eQTL identification
studies. The overlaps-variants in the SNPs genotype linked to a trait (results from transcriptomics)
that link with variants regulating the messenger

Creating a complete toolbox
To perform GWAS and transcriptomics on samples,
scientists use a collection of tools, and Thermo Fisher Scientific offers a complete eQTL toolbox (see
"A Complete Workflow for Discovery and Verification of eQTLs in Lung Adenocarcinoma;" page 6). In
GWAS, the nucleic acids, both DNA and RNA, can be
extracted from the same sample preparation using
Invitrogen™ RecoverAll™ and then quantified with
a Thermo Scientific™ NanoDrop™ spectrophotometer or Invitrogen™ Qubit fluorimeter. After that, the
Applied Biosystems™ Axiom Precision Medicine Research Array (PMRA) or other genotyping array can

Thermo ebook on eQTL

Table of Contents for the Digital Edition of Thermo ebook on eQTL