We are extracting Total RNA (using Trizol and Qiagen kit) from whole
flies and then using a Agilent Bioanalyzer to check the quality of
the RNA. My question is about how to interpret the Bioanalyzer output.
There seem to be 2 different interpretations of the patterns of peaks:
1. According to the UK Drosophila Affymetrix array facility the 18S
and 28S peaks are quite separate from one another , and the double
peak is interpreted as the 18S (see http://www.mblab.gla.ac.uk/igf/
agilent.html). Advice from an Agilent representative agrees with
this: the 18S are often divided into two peaks and the 28S is very
2. In both TAHOE et al (2004, Journal of Gerontology: Biological
Sciences; Vol 59A (9) 896-901) and in MEE (2005, Invertebrate
Neuroscience; vol 5 (nos 3-4) 189.195) the double peak is interpreted
as if the 18S and 28S peaks are very close to one another and the
smaller peak to the right of the double peak is ignored.
We almost always get the double peak, and a much smaller peak to the
right of this but never is this peak as large as the UK Dros Affy
My question is which is the 18S peak and which is the 28S peak?
I would be delighted to hear from other researchers that use the
Bioanalyzer to examine RNA integrity!
ted.morrow from ebc.uu.se