Archive for the ‘Genetics’ Category

New ways to communicate science – Science-Rap

June 17, 2011

This fortnight I thought I’d do something a little different. Rather than a normal article, I thought I’d draw your attention to a group of science communicators who definitely have their own style. These people are part of a burgeoning group of science rappers.


Oort Kuiper
Jon Chase, aka Oort Kuiper, is a science communicator from the UK. Often working with another communicator Mark Brake, Jon takes his unique way of communicating science into the public by performing at schools, libraries and other community centres. Jon has been commissioned by organisations such as NASA to create science raps, and has performed at notable institutions such as the London Science Museum, the Royal Society, and the Royal Institution (GB).



With a background in aerospace, science and science fiction, his raps tend to focus more on human’s place in the Universe and how life relates to it. He gained some exposure for his 2008 rap Astrobiology, commissioned by NASA.





His other notable works include Life – An Autobiography, a six and a half minute journey through life on Earth.



A Better View reveals the world we live in through science and technology.



However Jon’s discography also includes topics as diverse as rain and genetics.



Alpinekat
One of the most well-known science rappers is Kate McAlpine, otherwise known as Alpinekat. The Michigan State University graduate was working as a science writer at the Large Hadron Collider in Switzerland when she first recorded Large Hadron Rap, featuring her and a number of CERN colleagues rapping and dancing as only scientists can. After being posted on YouTube, Large Hadron Rap has gone on to be viewed over 6.6 million times.





Despite initial scepticism from CERN management, Kate received permission to perform and record the video in and around the LHC. After viewing the finished product however, they were won over. “We love the rap, and the science is spot-on”, CERN spokesman James Gillies told National Geographic.



AlpineKat has gone on to make more science rap videos, including Rare Isotope Rap, and Black Hole Rap, below.




Tom McFadden
Tom, an instructor from Stanford University in California, approaches his science rapping a little differently. Not afraid to use technical details, his raps contain many more scientific terms and jargon, so they do require some prior knowledge. This makes them more useful for university students and scientists than the general public.



Nevertheless it is impressive he manages to rap around the jargon, and for those with a cell biology background, they’re quite entertaining.



For example, Put Some ACh Into It explains the two sides of the autonomic nervous system – the signalling system that the body uses to unconsciously control the body. The autonomic nervous system controls things such as heart rate, digestion, breathing rate and perspiration, as explained in the video.



Get Taq explains several commonly used biotechnology tools, such as replicating DNA, connecting pieces of DNA together, producing custom proteins, and even genetically modifying mice to investigate what role particular proteins play in an animal.



These three artists aren’t the only exponents of science rap, but they’re amongst the ones to keep an eye on. And as science communicators forever look for new ways to engage with the community, they’re the ones at the forefront of a new way to connect with the public.



Check out Jon, Kate and Tom’s raps, plus others at scienceraps.co.uk.

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Sexual attraction – Part 2

April 7, 2011

Last post talked about the effects that the sex hormones oestrogen (females) and testosterone (males) have on attractiveness to the opposite sex. While the do have a major role in assisting our search for appropriate mates, there are other factors.

 

Physical features

The effects of sex hormones on facial features has already been described, however it was believed for a long time that the waist-hip ratio was a prime determining factor for measuring attractiveness of women. Body fat is an indicator of fertility – too little or too much reduces fertility, possibly explaining why very thin or overweight people are not considered generally attractive. A ratio between waist and hip size of 70% has been thought of as optimal. However, waist-hip ratio is an overly simplistic way of determining physical attractiveness, and it is now considered to be a combination of 25 measures which describe physical attractiveness, one example being leg length.

 

This idea of physical measurements determining attractiveness is not confined to humans. The female widow bird for example will preferentially seek a male with a longer tail. In fact if the male birds’ tail is artificially shortened, they will then be less attractive to females.  So while there are thought to be around 25 measurements that define human attractiveness, the widow bird’s tail is the major determinants of their attractiveness.

 

Gene matching

In nature there are instances where animals will preferentially seek out animals which have similar genes. The Gouldian finch is found with one of a number of head colours, and when it comes to mating will prefer to partner with another animal of the same head colour. In fact, if it mates with an animal of different colour, the bird will get rather stressed out about it. This mechanism exists to maintain a proper balance in the gender of the offspring, mating with a different head-colour bird will produce more male offspring, so this distaste for mating with different coloured birds has evolved to maintain proper population size and gender ratios.

 

In humans it is somewhat similar; we tend to look for someone who is similar and not too different from ourselves as that means our genes will be a good match. However, we also look for someone who isn’t exactly the same, there is a balancing act involved, and there are several mechanisms to help that. For example, part of the immune system is called the major histocompatibility complex, or MHC, which is slightly different from person to person. Women can actually (subconsciously) detect the MHC-type of a male, and will preferentially choose a male who has a slightly different MHC than their own. This is for two reasons, firstly some similarity means the two people are genetically similar, and secondly, a slightly different MHC will mean their immune system is slightly different, giving offspring a potentially greater variety in their immune system. Strangely however, women on the pill are unable to pick up a male’s MHC.

 

These features which are attractive between men and women are also present between homosexual couples. What straight men look for in women, gay men look for in men. Similarly, gay men actually prefer the smell of gay men over the smell of a straight man, so there does appear to be a difference in pheromones.

 

These olfactory mechanisms play an important part in maintaining genetic variability by acting as an incest avoidance system. There are several mechanisms which exist, not only in humans, to maintain genetic variability by effectively finding someone closely related ‘unattractive’, including the MHC-type detection. Again, humans look for someone who is similar but not the same, and different but not wildly different, so these mechanisms exist to maintain that divergence.

 

Love and sexual attraction can be hard to define and quantify, and a large reason comes down to the physiological mechanisms which have evolved over many generations and have become ingrained. Cues such as hormonal cycles which subtly change the appearance and attractiveness of someone, subconsciously assessing someone’s fertility, or detecting the MHC-type of a partner play a role which we never notice and never consider. But nevertheless they’re there and while other factors such as personality play a role, inevitably it’s these unconscious reasons which will determine whether or not we find someone attractive and an ideal mate.

 

Thanks go to Bill von Hippel from the University of Queensland and Rob Brooks from the University of New South Wales

Sexual attraction – Part 1

April 6, 2011

Apologies for the late posting of this fortnight’s articles, I needed to wait for an embargo to lift prior to publishing.


Finding a mate is one of the most important tasks for every organism which reproduces sexually. While people say they have different ‘tastes’ in an ideal mate, in fact there is a large amount of commonality between what humans define as attractive, and at the risk of taking the ‘fun’ out of finding a mate, there are specific physiological reasons for sexual attraction.

 

Attractiveness may have hormonal reasons

One of the major hormones in the reproductive system of women is oestrogen, with the male equivalent testosterone. As well as having vital roles in regulating the reproductive system, they also affect the attractiveness of a person.

 

A female with high oestrogen levels will usually have a rounded face and large eyes, two factors which are generally regarded to increase attractiveness. When an audience is shown 2 computer generated faces with one having these features but otherwise identical to the first, nearly 70% of people find the “high-oestrogen” face more attractive, with the proportion of women and men who find it attractive being around equal.

 

Humans aren’t the only animals to have facial features altered depending on fertility state. The face of female rhesus macaques (a type of monkey) darkens when they are fertile, with the changes similarly linked to hormonal cycles. Interestingly, males can actually recognise the fertility states of female partners from these features. The more familiar a male is with a particular female increased their knowledge of fertility states from these cues.

 

Similarly, a male with high-testosterone will usually have the attractive square jaw and angular face, and when an audience is shown computer generated faces and asked to choose which is more attractive, the “high-testosterone” face comes out as the preferred face, again by nearly 70% of the people. Interestingly however, while the same number of men and women found the “high-oestrogen” face attractive, men were less likely to find the “high-testosterone” face more attractive than the “low-testosterone.”

 

There is an evolutionary reason for an increased attractiveness as a result of high levels of sex hormones. Women with high oestrogen have high fertility levels, and so are desirable mates due to an increased ability to produce offspring. Similarly, testosterone levels in men are a sign of high quality genes, which are sought after to increase the chances of offspring survival (remember all these processes evolved long ago when living conditions were much harsher). Testosterone in men actually acts as an immunosuppressant – it reduces the activity of the immune system. While this may seem a disadvantage, the ability of the male to have survived to procreation age shows that they must be genetically strong to have been able to overcome any infections with the reduced immune system. For these reasons, high sex hormone levels are considered to be desirable traits in a mate.

 

Supporting this idea that high testosterone is a sign of genetic strength, when women ovulate they tend to become even more attracted to the high-testosterone males, showing there is an evolutionary mechanism to try to choose mates with ideal genetic characteristics.

 

Although testosterone is a sign of genetic strength, it does however also increase some undesirable traits when choosing a mate. High testosterone does increase aggressiveness, making the male less nurturing towards offspring, and also increases the male’s desire for what is called sexual novelty; in effect the male will be more likely to be unfaithful as they tend to seek different sexual partners. So for women there is a trade-off to be made between high and low testosterone, to balance the advantages and disadvantages, and it may also explain why some women in particular seem to like “bad boys”, they would like have high testosterone levels. For men however, there is no trade-off, they will generally just seek high-oestrogen (and hence fertile) females.

 

For these reasons, women may tend towards a lower testosterone male for the reasons of producing offspring as although the offspring may be of lower genetic quality, they may be more likely to be provided for by the father. However, often testosterone levels in men will drop after producing offspring – a mechanism to reduce aggressiveness, promote nurturing behaviour, and increase faithfulness to a single partner. Women’s preferences also tend to change slightly with age, with older females more likely to prefer lower testosterone males.

 

As these effects have been developed due to evolutionary pressures and are linked to genetics and hormones, they are consistent across cultures. No matter where people come from, they tend to look for the same features in a mate.

 

Thanks go to Bill von Hippel from the University of Queensland and Rob Brooks from the University of New South Wales