When did insects first crawl out of the ocean? What caused them to take flight? Endless questions about the most abundant group of organisms on earth can now be answered.
80% of known species are insects. Insect diversity supports our environment and damages our crops, spreads diseases and might cure them too, and has the potential to shed more light on how and why we evolve. Up to now, scientists have succeeded to look only at twigs and branches, without sufficient data to tie the images into a proper tree of life in the insect family.
A transcriptome is a bit different from a genome, which is more commonly discussed in relation to genetic studies. The genome is all of the DNA, the famous two-stranded helix that gives our cells the instructions that create and sustain life. In order to transmit those instructions, the cell opens up the helix a bit at a time and makes a copy of the message in single-strand RNA molecules. All of the RNA molecules in a cell at a given time are referred to as the "transcriptome".
Because the transcriptome consists of the working machinery of the cell, it represents the active parts of the genes -- the parts that actually encode proteins and influence the current appearance and functionality of the organism.
The effort did meet a bit of an obstacle. It was not possible to handle as much data as 1000 insect transcriptomes would have involved. Nevertheless, the study encompasses a jaw-dropping 1478 protein coding genes from 144 carefully selected species enabling researchers to put the puzzle pieces in their places on the insect tree of life.
Previous studies typically looked at only one or two genes, or looked only at physical characteristics or functional capabilities (like metamorphosis! What can we learn from organisms that change so radically throughout their lifecycle?).
To sort out the immense amount of data, entomologists, insect paleontologists, and genetic researchers were joined by computational scientists developing software to analyze the findings.
Did you know insects are related to shrimp? Think about that the next time a friend invites you to taste the new trend in edible insects.
So when did creepy-crawlies take their first steps on six legs? The study shows that "insects originated at the same time as the earliest terrestrial plants about 480 million years ago". The report suggests that insects had as much to do as plants in "terraforming" the earth's ecosystems.
And when did they learn to fly? About the same time plants surged upward, forming the earliest forests.
The data and techniques developed in this study will be a boon to future research into a somewhat overlooked bio-resource -- hopefully much to the benefit of insects as well as to man.