Bio-molecular signatures associated with psychiatric disorders

This article investigates utilizing methylation profiles at CpG I of the BDNF gene in diagnosing depressive disorders.

Q&A with Leroy E. Hood

This article is a Q&A with Leroy Hood. Hood pioneered the automated DNA sequencer while at Caltech in the 1980s, and more recently has he been a vocal proponent of the Human Genome Project. In this interview, Hood fields questions about the progress in the field of personal genomics, commenting upon the recent wealth of data available to people who wish to sequence themselves and the benefits of potential medical applications of this data.

Genomic parasites responsible for the birth of mammalian pregnancy

I thought this was pretty wild - and it happened right across the street in ESC!

Gunter Wagner (and team) set out to investigate novel phenotypes/cell types - in particular, mammalian pregnancy. How did carrying developing young in the womb evolve?

Wagner and team identified 1500 genes that were unique to the uterus of mammals and involved in placental development. The big kicker? The expression of these genes is under control by transposons. Essentially, large-scale morphological changes (aka - the emergence of mammalian pregnancy) was not due to mutations within key genes, but rather is attributable to the establishment of a novel gene regulatory network (modulated by transposons).

Processed pseudogenes: the 'fossilized footprints' of past gene expression

Though modern technology has allowed the access and sequencing of ancient DNA, evolutionary geneticists would like to access ancient ancestral organisms' transcriptomes in order to investigate more into the evolution of gene expression. Because of the fragility of mRNA and therefore near impossibility of ancient extraction, researchers want to use pseudogenes, which are non-functioning relatives of existing genes that no longer code for proteins. Each expressed gene purportedly has a certain number of "pseudogene offspring", and so researchers believe that these genes can be used as "fossilized footprints" of former gene expression. This process is not wholly accurate, and researchers stress the usefulness of extracting ancient transcriptome information for future studies of evolution.

Ancient DNA extraction techniques in ancient bone

Archaeological research attempting to isolate ancient DNA from skeletal material has met with many difficulties. The issues of preservation, high potential for false negatives, and varied depositional environments have all proved to be confounding factors when attempting to extract genetic material from ancient remains. This study utilizes PCR analysis to measure (mt)DNA quantities in various hard tissues in ancient human and bovid material in order to determine the most promising regions of bone for this type of analysis. They found that using a low speed drill as opposed to high speed drilling or bone pulverization yielded significantly more (mt)DNA. In addition, they found that tooth cementum, as opposed to the more commonly utilized tooth dentin yielded the most (mt)DNA. Finally they found that different types of skeletal material exhibit consistent patterns of exponential fragmentation across varied types of depositional environments.

Evolution's past is modern human's present

In this article it is explained that modern African populations interbred with "archaic" humans. The study, done by Michael Hammer and his team, took the DNA sequence from 3 different African groups and found that part of their genome comes from archaic humans who were biologically compatible to the point of producing fertile offspring. Although fossils have not yet been found to support the findings done by this research, the researchers were able to infer based upon the very thorough simulations that were done. The groups that existed in the past are believed to have come from Central Africa. The article also suggested that interbreeding with archaic humans in Africa lasted much longer than interbreeding in Europe or Southeast Asia.

Cloning of Neanderthals?

Like homo sapiens, the Neanderthals were smart, made tools, and had a complex social system that involved the respectful burial of the dead. And yet, it was our ancestors who survived and not this seemingly equally viable sister species. Sequencing the Neanderthal DNA has allowed scientists to pinpoint their evolutionary relationship to us, answer fascinating questions about their intelligence in relation to ours and whether or not we interbred, and allowed scientists to hazard guesses as to the cause of their downfall, which will inevitably shine light onto our own vulnerabilities. However, along with this insight from a complete genome sequencing of Neanderthal DNA comes the moral question of cloning. Cloning is a complicated process involving the replacement of a nucleus of a stem cell with a nucleus containing the genome of the desired parent. Sequencing the DNA of a deceased organism is already complicated, but that would only be the start (the really tricky part is synthesizing the nucleus, which scientists believe could be accomplished by individually altering the genetic material of a human nucleus, nucleotide by nucleotide). Thus, we are definitely quite a ways away from a cloned Neanderthal, but the idea definitely represents yet another interesting moral dilemma that genome sequencing brings to light. Cloning in general raises moral issues, in the creation of life as "playing God" and in the use of fetal stem cells. However, there is also the issue of bringing back a species whose natural ecosystem has long-since been destroyed, a world in which it can exist only under study in a laboratory. This issue is even more controversial as it is no ordinary extinct species (like the wooly mammoth that scientists at Kyoto University in Japan intend to reserect), but our own sister species, a species that science indicates to have potentially been as sentient and conscious as we are. To clone a Neanderthal would inevitably bring into discussion cloning of one of our own.