Here is a new arthropod genome paper:
Genome Sequence of the Pea Aphid Acyrthosiphon pisum.
The International Aphid Genomics Consortium 2010
PLoS Biol 8(2): e1000313.
http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.1000313
Aphid has a lot of genes: 35,000 compared to 15,000 to 20,000 in
other insects. There are various speculations on this large
number (including artifacts) but I see evidence that species gene
sets are often missing what expression and orthology searches says is there.
The asexual biology of aphid also provides opportunity for keeping extra gene
copies perhaps more readily than in sexual bugs. As there is rather large
variation in genome sizes, and gene numbers in other phyla, it isn't unexpected
to see this range in arthropods, from 10,000 in the louse
to over 30,000 in aphid and daphnia.
-- Don
