Newsflash! Can we revive the Dodo?

Earlier this week, work done at the University of Newcastle in Australia ‘revived’ a species of frog that has been extinct since 1983. Using their ‘sophisticated cloning technology’, it is hoped that they will be able to resurrect many other extinct species, such as the Dodo.

The frog that the group, lead by Professor Mike Archer, was working on, was a bizarre species of gastric-brooding frog called Rheobatrachus silus. It’s weird because it is only one of very few animals that gives birth through its mouth. The frog would swallow its own egg, brood its offspring in its stomach, until it is matured enough to ‘be born’.

 

Photograph of Rheobatrachus silus, the gastric-brooding frog.

Not quite the Matryoshka doll, but you can imagine. The eggs are coated with prostaglandin, a substance which stops the stomach from producing acid that will digest its young.

The group utilized an established method of cloning called somatic-cell nuclear transfer (SCNT). They first found an egg from a similar species of frog – the great barred frog, discarded its nuclear content, and then replaced it with the nucleus of the extinct frog. Since the nucleus contains almost all the genetic information, the new chimera will contain all the instructions it needs to make a new frog – the extinct frog.

The nuclei of the extinct frog was preserved inside tissues collected in the 1970s, which was kept in a deep freezer for more than forty years.

The experiment was a moderate success – some of the eggs spontaneously divided and grew into a ball of cells, forming the early embryo. However, none of these eggs survived for more than a few days. So technically, the frog was not revived per se, although the group is confident that it is only a matter of time before it is a success.

“We’re increasingly confident that the hurdles ahead are technological and not biological and that we will succeed” Professor Archer said.

In fact, this project, code named Lazarus, was a collaboration of experts from many different universities in Australia, including the University of New South Wales and Monash University. And they are not alone in this movement to revive lost species.

TED (Technology, Entertainment and Design) teamed up with the Long Now Foundation and National Geographic Society, to host a one-day conference, TEDxDeExctinction, on the 15th March, 2013, at the Grosvenor Auditorium in Washington, DC. Their aim was even bolder – “reviving extinct species and re-introducing them to the wild.” It brought together geneticists like George Church from Harvard Medical School, conservationists like David Burney, ethicists, biologists and other scientists together to explore this possibility of ‘de-extinction’. Many species were discussed, including the woolly mammoth, dodo, Tasmanian tiger, Cuban red macaw and New Zealand’s giant moa.

The drive behind this movement, which is gaining momentum, is to preserve, and now possibly enhance, the biodiversity of our ecosystem. They hope this movement will also make people more aware of protecting currently endangered species.

Exhibits of models of the long-extinct Dodo (Raphus cucullatus), from Oxford University Museum of Natural History

The long-extinct Dodo (Raphus cucullatus) might soon escape from the display cases of museums, and onto our dinner plate – truly food for thought.

Although the paper is not published yet, you can find the press release here.

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Why does hair turn gray?

It was not so long ago since I found the first gray hair ever on my head. It is a reminder that I am getting older, but none the wiser. But why do hair turn gray in the first place? This might be a little more technical than my previous post, but I promise you it makes sense. So first, let’s see what a hair really look like, under the layer of…hair.

Diagram of Hair Follicle

The hair is only gray here because the diagram is black and white

So you can actually think of a hair as two parts – the shaft is the part that you see, and the root is the bit in your skin that you don’t see. Shaft you see, root you don’t. So far so good. The root is embedded in the hair follicle, which is the layers of skin cells surrounding the root.

Most of the hair is made up of a protein celled keratin; but what gives the hair (and skin for that matter) its colour are pigments called melanin. These pigments are produced by cells called melanocytes that lives in the hair follicle. If you have black/dark hair, you hair is probably pigmented with a version of melanin called eumelanin; if your hair is more orangey, then pheomelanin is probably responsible. Which pigment you have is encoded in your genes. If one of your biological parents have dark hair, you’ll have dark hair too! You can think of this as a child painting – the keratin is the canvas, the melanin is the paint, and there are essentially two different types of paint, which is determined by which one the kid’s parent gave them.

So, when hair grow, it grows from this hair follicle. The melanocytes inject melanin pigments into cells that make the keratin proteins (keratinocytes), and so the melanin is incorporated into the hair and gives it its colour. It will then move up and into the shaft, and express its existence in glorious colours. Again with the painting analogy – the paint is ‘injected’ onto the canvas, which is then moved out to be exhibited by the world. As we grow older, the melanocytes gradually loses its ability to produce melanin, and so the hair loses its colour; as if a painter can no longer paint and are simply shipping out blank canvases (they now call this modern art).

So your hair turns grey not because of some white pigment, but rather the proteins that make up your hair is naturally white. Jolly good. To my fellow readers – rest assured, when I start balding, there will be a post about it.

Comic strip about gray hair

True story

Why do we get goose bumps when we are cold?

No, not the Goosebumps written by Robert Lawrence Stine. We are talking about goose bumps. If you want to sound smart, you may call it cutis anserina. We get goose bumps when we are cold, or when we are scared, amazed, or any of a range of emotions. We can’t really help getting them neither, they come and go as they like; this is what is called a reflex. Reflexes are involuntary/automatic – as soon as it’s cold, your hair stands up all by itself – you can’t control it. If you tap your knee in a certain way, your leg instinctively kick – this is reflex! The reflex responsible for the knee jerk is called the patellar reflex, whereas the reflex that controls goose bumps is named the pilomotor reflex.

http://dilbert.com/strips/comic/1991-06-28/

Blame the reflex

So why do we get goose bumps when we are cold?

Imagine you are in a cold room. Your body will try to keep you warm by metabolizing the food you ate, or ‘burning’ your fat, to create heat. If your skin is very smooth, you body heat will simply heat up the neighboring air, and because hot air rises, the heated air would simply go away. This air must then be replaced by some other air – the rest of the cold air in the room. You won’t feel warmer because the the heat is lost quickly.

Now imagine your skin having a lot of hair. When you feel it’s cold, your hair stands on end. The air surrounding your skin is now less able to move freely, because your hairs are in the way – you’ve kind of trapped the air to stop it going away. The warm air are kept close to the skin and so we feel warmer. It’s like having a thin hair coat that keeps us warm. And so goose bumps keeps us warm in the cold.

The skeptical of you will ask – can these tiny hair really trap air? The answer is no. So what’s up with the explanation I just gave you? To explain this, we have to remember that us humans – homo sapiens – are the result of hundred of million years of evolution. Evolution isn’t perfect – it creates a lot of useless things. In fact, many of the DNA that encodes you, are actually useless. This is because evolution is a random process, and not directed. Think if we randomly arranged 28 random letters, how many non-sense words are we going to get before we make the word ‘Antidisestablishmentarianism’? If you actually tried, you’ll realize evolution gives us a lot more junk than anything useful.

If you look at chimpanzees, or gorillas, or monkeys, they are pretty hairy. The same reflex can be found in these animals. But because their hair are so thick, standing the hairs on end when they are cold can actually trap the air to keep them warm. These animals evolved from the same ancestors as us. Over time, we lost our thick, dense mass of hair because we no longer need it. But the reflex that makes our hair stands on end when we’re cold are still here – think of its a remnant left by evolution.

Ham the Chimp

Hairy.

And so even though goose bumps are practically completely useless now, it does remind us that we are an imperfect product of evolution. Who knows, maybe in a few million years we won’t get goose bumps anymore. That’s if we’re still alive.