Hi everyone! I meant to post this last Sunday, but as you can see, I’ve been running a little behind schedule. Nevertheless, it’s time for a short review of what has been happening in the world of science, and last week has been an interesting week as far as that goes. Let’s start with the big news.
Announcement of the 2015 Nobel Prizes
Earlier last week, the Nobel Assembly at Karolinska Institutet, and the Royal Swedish Academy of Sciences announced the names of the recipients of the 2015 Nobel Prizes in Physiology and Medicine, Physics and Chemistry. Here’re the announcements from the official website –
The Nobel Prize in Physiology or Medicine 2015 was divided, one half jointly to William C. Campbell and Satoshi Ōmura “for their discoveries concerning a novel therapy against infections caused by roundworm parasites” and the other half to Youyou Tu “for her discoveries concerning a novel therapy against Malaria“.
The Nobel Prize in Physics 2015 was awarded jointly to Takaaki Kajita and Arthur B. McDonald “for the discovery of neutrino oscillations, which shows that neutrinos have mass”
The Nobel Prize in Chemistry 2015 was awarded jointly to Tomas Lindahl, Paul Modrich and Aziz Sancar “for mechanistic studies of DNA repair“.
We’ll be exploring each of these awards in more detail in the coming week, along with a brief look at the life and career of each of the eight awardees.
Hands and Feet of ancient humans
In late 2013, a pair of explorers entering a cave in the Rising Star system in South Africa stumbled upon a narrow chamber filled with what looked like human bones. It soon became clear that the bones belonged to a human species that no one had ever seen before. Over several weeks of excavation and digging, more than 1500 bone fragments were found, belonging to at least 15 different individuals. The new species was named Homo naledi (a nod to the cave of origin, ‘naledi’ means ‘star’ in the Sotho language). Homo naledi had features both primitive and modern – diminutive in size, small- brained, but with a bone structure eerily similar to modern humans. This week, researchers published their analysis of the hand of Homo naledi, as assessed from bone fragments found in the Rising Star cave. According to their analysis, the structure of Homo naledi‘s wrist and palm is similar to modern humans, but the fingers are much more curved, suggesting that they were used for climbing trees and gripping branches. This is important because a hypothesis suggests that the bipedal (two-legged) mode of locomotion that marks humans as unique amongst primates evolved when early humans shifted their habitat from dense jungles to open grasslands. Curved fingers in an otherwise bipedal species, as seen in Homo naledi, suggests that these hominids had not abandoned the primate tree-living lifestyle yet, although they had managed to start walking upright. In a second paper in the same journal, the scientists also describe the bone structure of the foot of Homo naledi, proposing that these early humans were well suited to a bipedal mode of locomotion, as is shown by their predominantly human-like foot structure. Once more, however, the toes are more curved than modern humans, suggesting some level of versatility in locomotion. Homo naledi is the first species of human found with such modern hand and foot structure, coupled with a really small brain, and while the bones have not been precisely dated yet, the wealth of information they can yield about our prehistory can be immense.
Establishing the phylogeny of birds
Phylogeny is the branch of biology that deals with the question of how species arise, i.e. their evolutionary history. Birds, as a group, show more variation than any other class of land-living vertebrates, with over 10000 living species, and several that have gone extinct over the past few millions of years. Establishing evolutionary relationships between individual species has been notoriously difficult in the past. Birds are believed to have evolved from dinosaurs in the late Jurassic period (about 160 to 140 million years ago) and then diverged into several different species in a very short time, a fact which has made understanding the evolutionary relationships between individual species extremely challenging. In order to try and reduce some of this ambiguity, a group of US scientists carried out an exhaustive study of bird phylogeny by comparing the DNA sequences of 198 bird species, and using them to try and figure out evolutionary relationships. They found that there are five main clades (groups) of birds that are sister groups to each other. These five groups are – a) a clade containing swifts and hummingbirds b) cuckoos, bustards, pigeons, turacos, mesites, sandgrouse c) cranes and their relatives, d) the rest of the waterbirds and e) all other terrestrial birds. This is one of the most comprehensive studies of avian phylogeny published till date.
Contraception through gene therapy
The idea of immunocontraception has been around for a while, and has been used for controlling populations of certain wild and domestic species of animals. Basically, this method of contraception utilizes the fact that certain hormones and proteins are necessary for sexual maturation of gametes and hence for conception. If the body can be fooled into recognizing these proteins as foreign bodies, it starts creating antibodies against these proteins, which bind the proteins and inactivate them. So, if an animal is injected with concentrated fragments of such proteins, the immune system starts creating antibodies, leading to sterility. The problem with this method is that it is overly reliant on the individual’s own immune system, and can become less effective over time. To address this problem, a group of scientists at Caltech took this process one step further, and decided to reprogram the body’s cells in such a way that they start producing these antibodies without ever involving the immune system. They did this by creating a virus (AAV) which carried the gene for specific antibodies against GnRh (Gonadotropin releasing hormone), a hormone that is important for sexual maturation of eggs and sperms. They then injected this virus into the skeletal muscles of mice, causing the cells there to start producing the necessary antibodies. The virus, AAV, has no other ill consequences on the body. When injected into the muscles of male and female mice, the therapy produced long-lasting sterility.
Vaccines do not cause autism (again)
In 1998, Andrew Wakefield, a British medical researcher, published a paper in the acclaimed journal Lancet that claimed a significant association between the measles, mumps and rubella (MMR) vaccine and the incidence of autism. The paper received huge media coverage and attention. Several large epidemiological studies were undertaken to establish and understand this link – however, none of these studies could find any association between the MMR vaccine and autism or reproduce any of Wakefield’s data. Wakefield’s original paper was later proven to be fraudulent, leading to a full retraction of the paper in 2010. Andrew Wakefield was later found guilty on multiple counts of dishonesty and professional misconduct by the General Medical Council, and subsequently stripped of his license to practice medicine.
However, the fear established in the public mind had taken hold by then, and from 1998 to 2015, the number of American parents who have refused to allow vaccination (the so-called ‘anti vaccination’ movement) for their children has risen, as has the incidence of measles, a disease that was believed to have been eradicated in the US in 2000. Thimoresal, a mercury-containing organic compound used as a preservative in vaccines, is believed by many parents to be responsible for causing autism, although no scientific evidence exists so far to suggest this. In order to investigate this link clearly, scientists in Texas, USA, administered thimoresal containing vaccines to 79 rhesus monkeys, and did an extensive survey of the behavioural and neurological consequences. Using several measures of brain function and abnormal behaviour, the authors found no significant abnormalities in vaccinated monkeys. The study was published in PNAS last week, and has again attracted significant media attention. Safeminds, an organization with anti-vaccination policies that helped fund the research has come under ridicule in the popular media, and recently released a statement stating that there were problems with the published study.
“The vaccine primate study in question consisted of multiple phases. The initial phase found a series of negative effects in infant reflexes and brain growth among those exposed to vaccines. The second, recent phase purported to find no effect. SafeMinds has concerns about changes in the study design protocol and analysis that may have led to these contradictory results. We are in the process of collecting and reviewing additional information regarding this study.” – Safeminds
This adds to the significant breadth of literature that supports the fact that there is no association between vaccines and autism and that the health benefits of vaccines far outweigh their risks.
Different life goals of men and women
The low representation of women in high power jobs is a significant challenge for any society geared towards equality for women. While several studies have focused on work environments and deterrents to the progress of women in the work area, comparatively little research has been done to check if there are differences in attitudes of men and women towards work-related achievements that could contribute to this skewed representation. In a survey based study, researchers found that men and women saw high-power jobs as equally attainable. However, women appeared to find these jobs less desirable, and associated with more negative consequences, such as stress, and decline in interpersonal relationships. Also, when asked to list life goals, women listed a lower percentage of power-related goals than men. There is no way to tell whether this reflects an inherent difference in mindsets of men and women, or is a consequence of the differential outcomes of being in powerful positions for men and women, given that women tend to face much more hostility and aggression when in powerful positions than men.
So, it has been an interesting week, overall. I’m really excited about the coming week on Scientific lens because we will be looking at each of the nobel prizes and their winners in detail, starting with the Nobel Prize in Physiology and Medicine. Watch this space for more news and opinions, and have a good week . 🙂