Evil Twin’s Downfall

So what if we have an evil twin, like in the movies? If he/she commits a murder, and DNA evidence is found in the crime scene, both you and your evil twin will be suspects, since you share the same genetic material. Although this is a rare and unlikely scenario, it is definitely a possibility, and has actually happened several times throughout the years.

Usually, this will end in no one being prosecuted, since it would be impossible to determine which twin did it, and sending both to jail would be terribly unfair to the innocent sibling. A new option for the police in these cases is to analyse the DNA of both twins in incredible detail, searching for any slight variations that may have randomly occurred due to mutations and changed the genetic code, but this option takes a lot of time (over a month) and also happens to be very costly.


Now we can find out which twin actually did it

However, scientists have now come up with a sort of an upgrade to this method. Instead of looking for mutations, which occur randomly, they would look for differences in the DNA strands that have been caused by their way of life. These modifications are called epigenetic changes, and instead of causing a gene to change its sequence of bases, it just modifies how it is expressed into a protein. It can do this by adding a methyl group (-CH3) or by altering the histones in our DNA: the proteins that help condense our genetic information into a more compact shape so it can all fit into the nucleus of a cell.

These changes can be inherited, which would be unhelpful since both twins can have them, or caused by environmental factors, which would also be unhelpful if the twins have lived close together in the same conditions. Fortunately, very small differences can cause these changes, specifically in the early stages of the embryo’s development, so although still rare, these changes do exist in twins.

In the specific case of epigenetic changes by methylation, this would mean that the DNA strand is now larger, and has more molecules in it. This would increase the forces of attraction and increase its melting point. Since both twins will have different changes, and therefore different amounts of methyl groups, their DNA would not melt at the same temperature. So comparing their DNA’s melting temperature with that of the DNA found in the crime scene can tell the police which of the two twins did it, and solve the mystery in a much faster and cheaper process, as you only have to heat the suspects’ sample.

Puppy Dog Eyes

Dogs are the most popular pet in the world. They’re loyal, loving and most importantly, cute. But the reason we actually have them as our pets and may feel a connection to them lies beyond the heart, and in the realm of brain chemistry.

Humans release a hormone called oxytocin, the so called love-hormone, which creates feelings of affection and caring. It is produced by a mother gets when she stares into her child’s eyes, or by a spouse looking at their partner. And now, scientists have discovered, it is also liberated when a person makes eye contact or pets their dog, causing a bond to be formed. But, it’s not a one-side bargain: dogs also get a rush of oxytocin in their body, which makes them feel an emotional connection with their owners.

The experiment that discovered this looked into a group of people and their dogs, from breeds like Miniature Schnauzer or golden retrievers, and had them play in a room for half an hour, during which time they obviously touched and looked at each other. Before the test, the animals gave a urine sample, and after playtime was over, they gave another one. Oxytocin levels for all dogs were significantly higher after having spent time with their owners.

puppy dog

Can you feel the oxytocin flowing?

To investigate this further, they administered two solutions onto the dogs’ noses: on some, they sprayed an oxytocin solution; on others, they sprayed a salt solution to act as a placebo. The results supported the previous theory: those being sprayed with oxytocin spent more time looking into their owner’s eyes, and these corresponded by releasing more oxytocin into their system. But there was more to it. This effect only happened in female dogs. Male dogs did not provoke any change in behaviour or oxytocin levels. Although the reason is still not fully understood, and will be researched in future experiments, a possible theory is that in males, oxytocin can also cause animosity towards other people.

Interestingly enough, when the process was repeated with wolves and their owners it didn’t produce the same results, despite dogs and wolves being closely related. This may suggest that this mechanism was developed at a time when wolves and dogs were apart, such as when humans had already domesticating them.

However, don’t use this method to try and bond with any other wild animals. This could only work with dogs, as they are the only species other than humans that are known to release oxytocin because of eye contact. Usually, in the animal kingdom, eye contact actually means defiance, so it could get you in a lot of trouble…

Balding Irony

Baldness affects many people (mostly men) at some point in their lives and a lot of research has been carried out to learn how to prevent it. The secret to doing so might be the most ironic treatment ever: to prevent going bald, pluck your hair.

The science of hair growth is more fascinating than it may seem at first sight. Hairs actually go through cycles: first they grow thanks to the stem cells in the follicle (the anagen phase), then they stop growing (the rest phase), and lastly the hair falls out. But if you manually remove the hair at any of these phases, an interesting process is triggered. The follicle will release cytokines, specifically the CCL2 type, which is a chemical that attracts white blood cells. When these cells arrive, they also release their own set of chemicals that stimulate stem cells so they start producing hair again. However, what’s the point of plucking one hair so that it grows if you already have it?

Well, there’s a trick. Scientists at University of Southern California, Los Angeles, did some experiments with mice where they removed a handful of hair on a specific area of the mouse’s body, and to their surprise, found that not only did the patch of hair grow back, but also stimulated growth in others areas. The catch is that this only happened if a certain amount of hair was removed: there was a threshold for the amount of hair that needed to be pulled out for others to be stimulated.

bald head

Should’ve plucked his hair more often!

This is because the CCL2 signal from one follicle isn’t very large; you need CCL2 to build up so the effects are much stronger and can affect a larger area of the skin. In the specific experiment they carried out, the lowest number of hairs that had to be removed was of 200, which lead to the growth of 1200 hairs. The way these hairs can communicate with each other by accumulation of chemical signals is called ‘quorum sensing’, and it causes the hairs to act like a collective group, as if taking decisions together.

Although the study was carried out on mice, the researchers don’t rule out the fact that it could somehow be used in humans, although some modification may be necessary. It also shows the increasing complexity of the immune system, and possibly sheds some light as to how the mechanism of regeneration is controlled.

The 6th Sense

We are used to people talking about the 5 senses: sound, sight, touch, smell and taste. But scientists are now working on improving these, and even creating a new sense that would enable us to experience the world in a much more heightened way.

For now, it’s all based on an experiment to help blind mice. Since this type of mice isn’t able to see, their sense of direction is severely handicapped. But in the University of Tokyo, a team used a compass like those found in smart phones, albeit a more complex version, and inserted it into the visual cortex of blind mice. It had two electrodes attached, each connected to a hemisphere of the brain. They fired up, sending electric impulses to the brain, whenever the mice’s head turned a certain amount of degrees away from the north direction. Depending on how many degrees, it would change the intensity of the signal on each hemisphere, so for example, when the mouse faced south, the neuroprosthesis would only send an impulse to the left hemisphere. After a week, the mouse managed to interpret these signals correctly and was able to orient itself using this compass, instead of the usual vision.

mouse compass

These mice have a compass in their brain, which helps them overcome their blindness

This was demonstrated by putting the mice in a labyrinth with a prize in the middle, and comparing normal mice, blind mice, and blind mice with the compass. After about 60 rounds of labyrinth trials, the normal mice and those with the compass behaved practically the same, finding the prize in a small amount of time, whereas the blind mice took longer. It seemed like the mice were able to create a map of the labyrinth in their heads, so no matter where they were placed within the maze, they managed to find their way around. Although this did not actually cure the blindness, it enabled them to find their sense of direction and be more independent.

What’s especially interesting is not only that the rats were actually able to ‘see’, but that they could detect this foreign type of stimuli and understand and interpret it correctly. Even though they spent their lives without a compass in their head, as soon as it started working they were able to use it to their advantage, showing the great adaptability of these organisms. This could be extrapolated to use in human beings, and gives hope for a cure/alternative to blindness. Other scientists go further and suggest that it could open a path towards new types of senses, using stimuli like UV or infra red light that, together with receptors like this compass, we could use to see the world in much more complex ways, adding more senses to the pre-existent ones.