In work out of UCSF and Stanford, biologists and mathematicians have teamed up to create a complete three-dimensional branching pattern and lineage of the mouse bronchial tree. The tree is generated by three local modes, each controlled by a "genetically encoded subroutine, a series of local patterning and morphogenesis operations, which are themselves controlled by a more global master routine," the authors write in the abstract.
Several papers describe work done on small RNAs in the fruit fly. Three separate groups have found that a new, third class of small RNAs in Drosophila, called endogenous short interfering RNAs (esiRNAs) bind to Argonaute 2 in somatic cells. Japanese researchers have found that AGO2, a subfamily member of the Argonaute proteins, associates with this class of 20- to 22-nucleotide-long RNAs to silence both protein-coding genes and mobile elements, such as transposons. Cold Spring Harbor Lab's Greg Hannon and Julius Brennecke and Memorial Sloan-Kettering's Eric Lai publish similar findings in this issue.
In book reviews, Robert Weinberg reviews Henry Harris' new translation of Theodor Boveri's seminal work, Concerning the Origin of Malignant Tumours. Boveri, who died in 1915, is best remembered for his idea that not only are chromosomes responsible for transferring heritable traits, but also that chromosomal abnormalities cause cancer. "For those biologists among us who are interested in how we got to where we are, this book makes fascinating reading, even if it does not lay down an accurate trail of previous discoveries," Weinberg writes. "This book takes us back to the humble beginnings of this now thriving field."