Breaking Report: Cross-Species Transgenesis

Also on my desk today--a pair of papers on techniques relevant to cross-species RNAi rescue.

Ejsmont et al. (2011) Recombination-mediated genetic engineering of large genomic DNA transgenes. Methods Mol Biol. 772:445-58. PubMed ID: 22065454.

Ejsmont et al. (2011) Production of fosmid genomic libraries optimized for liquid culture recombineering and cross-species transgenesis. Methods Mol Biol. 772:423-43. PubMed ID: 22065453.

RNAi in 30 Insect Species and Counting

On my desk today? A recently e-published review by Xavier Belles in the upcoming 2010 edition of Annual Reviews in Entomology, Beyond Drosophila: RNAi in vivo and functional genomics in insects.

Quote of the Week: Pseudo-Obscure

There seemed to be no end to the tricks that [Drosophila] pseudoobscura could do: one stock had odd sex ratios, another diplayed what seemed to be maternal inheritance, and so on. ... Pseudoobscura was so full of new tricks because it was an undomesticated, wild organism that had not yet been stripped of its natural genetic diversity, as melanogaster had long since been.

In, Lords of the Fly (1994) by R.E. Kohler, University of Chicago Press (Chicago, IL). pg. 260.

Quote of the Week: Diversity in Paradise

In the 1950s, when D. Elmo Hardy began describing the fantastic diversity of native Drosophila, he realized that a marvelous natural evolutionary experiment was occurring in the island forests. It was as if an earlier geneticist had locked specimens of a close relative of Drosophila melanogaster in a number of extremely large test tubes and allowed them to evolve for thousands or even millions of years ... In 1963, the Hawaiian Drosophila Project began diciphering the genetics and evolution of this amazing group of flies. Over 800 species of Drosophilidae in five genera have been recorded in the islands. This is nearly one-third of the total number of known drosophilid species in the world. Their diversity of form, ecology, and behavior far exceeds the range of known variations in the group outside of Hawai'i.

From Hawaiian Insects and Their Kin (1992) by F.G. Howarth & W. P. Mull. University of Hawaii Press (Honolulu, HI). pg.22.

All that and the American Wandering Spider, too

Seeing an announcement for CSHL Press's Emerging Model Organisms: A Laboratory Manual, Volume 1 (link) has made me consider adding a new feature to the blog, "Books I wish I Owned." But would just owning this book be enough? Glancing at the list of emerging models, I am taken by two things. First, I was amused to see Dictyostelium discoideum on the table of contents. PubMed records on Dicty go back as far as the 1930s. Poor Dicty, still "emerging" after all these years! And second, would someone please set up a tank of comb jellies (Ctenophora), a colony of snails (Ilyanassa), or even a small terrarium of moss (Physcomitrella patens) in my office? These sound like fun critters to have around.

Quote of the Week: Beach Colors

The insect-species confined to the sea-coasts, as every collector knows, are often brassy or lurid.

from Charles Darwin's The Origin of Species.

Quote of the Week: Diversity in Development

If morphological diversity is all about development, and development results from genetic regulatory programs, then is the evolution of diversity directly related to the evolution of genetic regulatory programs? Simply put, yes. But to understand how diversity evolves, we must first understand the genetic regulatory mechanisms that operate in development. In other words, what is the genetic toolkit of development and how does it operate to build animals?

In, From DNA to Diversity

Carroll, Grenier and Weatherbee (2001, Blackwell Science; p.13).

Breaking Report--DRSC Screen Data Published

What's on my desk to read today?  

Sessions et al. (2009) Discovery of insect and human dengue virus host factors. Nature 458:1047-1050. And see Editor's Note in the same issue of the journal.

This screen was performed at the DRSC using our whole-genome dsRNA library.

In the paper, the authors report the results of the Drosophila screen. Plus follow-up in human cells--they used siRNAs to target homologs of the fly genes they identified--and in the dengue virus vector mosquito Ae. aegypti--which they inject with dsRNA. The authors report "notable conservation of required factors between dipteran [fly & mosquito] and human hosts."

Using RNAi in three species to get closer to combating an infectious disease endemic in three continents and for which there is currently no vaccine or cure? Pretty darned cool.

Quote of the Week: Unstoppable Evolution

"Drosophila ... even now is spreading about the world and evolving new species. There is a great irony in the fact that, while the laboratory geneticist is showing his powers over nature by molding his fruit-flies as he pleases, the flies themselves are staging a quiet demonstration of their own."

Harold Oldroyd (1965) The Natural History of Flies. W.W. Norton, New York.

Hoverfly RNAi

What I'm reading today:

Lemke & Schmidt (2009) Evidence for a composite anterior determinant in the hover fly Episyrphus balteatus (Syrphidae), a cyclorrhaphan fly with an anterodorsal serosa anlage. Development 136, 117-127. [PubMed 19060334]

Why I'm reading it:

I am nothing like an expert in the natural history of flies.  

But I do know this about hoverflies (syrphid flies), they're a popular macro photo pic on Flickr.  They frequent flowers and like bees, do some work as pollinators.

The cover photo on the January 2009 issue of Development shows a hoverfly.  

And the corresponding article includes some RNAi work. In a study of genes that support anterior-posterior patterning (including bicoid and caudal) in a hoverfly, the authors use injection of dsRNA (for RNAi-based knockdown) and mRNA (for ectopic expression) to explore gene function.

It's fun to see RNAi being used successfully in this kind of evolutionary study on a fly that lacks the history of genetics that D. melanogaster has behind it.  

Helps remind me that even though I rarely think about RNAi without high-throughput screens in mind, there are many other ways it's having an impact--on our understanding of Drosophila's many fly cousins and of biology more generally.