【报告题目】：“BovB: Jumping the fine LINE between species.”
【 报告人】：David Adelson, Professor and Head of School of Molecular and Biomedical Science
The University of Adelaide, Australia
Genomes are made up of an abundance of different elements, including a vast number of repetitive elements. The proportion of the genome of each species that is composed of repetitive elements is vastly different. Drosophila have a significant quantity of DNA transposons (elements that replicate via a DNA intermediate), while humans have an abundance of Long Interspersed Nuclear Elements (LINEs), and cows have a remarkable 20% of their genome composed of retrotransposons (elements that replicate via an RNA intermediate). The study of repetitive elements helps us determine their effect on speciation, mutation and genome rearrangements. The discovery of a retrotransposon in cows, named BovB, is interesting due to its remarkable abundance and sporadic appearance across taxa. BovB has previously been found in snakes and marsupials with a remarkable level of conservation between distantly related species. The questions this poses are, “How is BovB found in such distantly related taxa without being present in the many other species that share a common ancestor?” and “How has BovB maintained its remarkable level of nucleotide identity?”. The likely explanation for this is horizontal transfer. Previously, a single horizontal transfer event, or possibly two, have been proposed in order for the element to move between squamates (snakes and lizards), ruminants (such as cows and sheep) and marsupials, but no vector has been determined. Our work shows that BovB is found across an even wider range of species than previously thought, and the distribution of the taxa on a phylogenetic tree built from the BovB elements indicates that up to nine transfers have occurred between the species in the tree, which includes African mammals, ticks, monotremes and horses, as well as the groups previously shown. For the first time we can show that reptile ticks, such as those studied here, are potential vectors for this horizontal transfer based on their BovB genomic content.
David Adelson is Professor and Chair of Bioinformatics and Computational Genetics and Zhendong Chair of Molecular Traditional Chinese Medicine in the School of Molecular and Biomedical Science at the University of Adelaide. Prof. Adelson is currently Head of School for Molecular and Biomedical Science and Director of the Zhendong Centre of Molecular Traditional Chinese Medicine. The philosophy of the Zhendong Centre is that complex molecular effects of TCM preparations will provide a molecular basis for understanding the mode of action of TCM and support integration into Western medicine. At present Systems Biology is a rapidly growing field precisely because it has become apparent that single gene or protein effects cannot explain or account for complex phenotype and behaviour at cellular, tissue or organismal scales.
Prof. Adelson’s current research also focuses on the computational analysis of repetitive, so called “Junk DNA” in mammalian genomes and on bioinformatic tools to mine Quantitative Trait Loci. He has led the analysis of repetitive DNA for the Bovine and Equine genome sequencing consortia and is currently working on the Elephant, Armadillo and Sheep repetitive DNA analyses. In addition to genome analysis, Prof. Adelson is also a founding member of bovinegenome.org, a single point of integration for bovine genome data.