Kerstin Lindblad-Toh talks
with ScienceWatch.com and answers a few questions
about this month's New Hot Paper in the field of Molecular
Biology & Genetics.
Field: Molecular Biology &
Genetics Article Title: Genome of the marsupial Monodelphis
domestica reveals innovation in non-coding
Authors: Mikkelsen, TS, et al.
Year: MAY 10 2007
* MIT, Broad Inst, 7 Cambridge Ctr, Cambridge, MA 02142
* MIT, Broad Inst, Cambridge, MA 02142 USA.
(Addresses have been truncated)
Why do you think your paper is highly
There are two primary reasons why the paper is highly cited: it described
the first marsupial genome sequence and a comparison between this genome
and those of placental mammals. Secondly, it provided major insights on how
vertebrate genomes evolve. It showed that regulatory elements account for a
large portion of the novel innovation within the placental lineage and that
many of these novel elements appear to have arisen from transposable
Does it describe a new discovery, methodology, or
synthesis of knowledge?
"I want to continue
to understand both the
function and evolution of the
human genome so that we can
identify genomic changes that
It describes a new discovery that roughly one-fifth of the conserved
non-coding elements (regulatory elements) in placental mammals are novel
innovations since the common ancestor of the marsupial and placental
mammals and that the origin of these elements is commonly from repetitive
elements. Thus it appears that innovation occurs largely by new regulation
rather than by the introduction of new genes.
Would you summarize the significance of your paper
in layman's terms?
This paper has important information about how mammals evolve. It suggested
that the major changes in the genome that lead to evolutionary changes in
body plans and development of mammals are caused by changes that regulate
when and how much of a protein is produced rather than by the addition of
In this paper we also discovered that these novel
signals of regulation often arise from repeat sequences, the portion of
the genome that is often called "junk-DNA." Our discovery therefore
could suggest that mammalian genomes contain such a lot of junk DNA
because it has been useful for allowing us to evolve and develop.
How did you become involved in this research, and were there any
problems along the way?
I became involved in this project by writing a
proposal to the National Human Genome Research Institute (NHGRI)
together with several members of the genetics and genomics community.
Our goal was to be able to study the genome of the opossum and compare
marsupial and placental mammals to better understand the human genome
through this comparison. Like all genome projects this was a large
collaborative project requiring the expertise and hard work of a few
hundred people, so coordinating these efforts was a critical part.
Where do you see your research leading in the
I want to continue to understand both the function and evolution of the
human genome so that we can identify genomic changes that underlie human
Do you foresee any social or political implications
for your research?
There should be no specific social or political implications of this
research, other than that it reinforces the importance of natural
Genome Sequencing and Analysis Program
The Broad Institute of MIT and Harvard
Cambridge, MA, USA
Guest professor in comparative genomics
Department of Medical Biochemistry and Microbiology