On Java, a stunning Volcanic island in Indonesia, you can find waterfalls, ancient temples, lush tea plantations and — you guessed it — the most expensive breed of chicken in the world.
Known as the “Lamborghini of chickens”, an Ayam Cemani will set you back up to $6000. Or, if you want to make an omelette, $16 per egg.
The chicken is known for the deep black pigment which is found not just in its feathers but also in its beak, bones and flesh. Historically, the bird has been considered mystical by locals, and has been included in traditional ceremonies for many years to bring good luck and ward off evil spirits.
What causes Ayam Cemani to be black?
The black pigment of the chicken is caused by a genetic mutation, which leads to a condition called fibromelanosis. While perhaps the most striking, Ayam Cemani are not the only example of this phenomenon. The adorable “Silkie” chicken (which looks a bit like a cotton ball with a beak) also sports the black flesh of fibromelanosis, along with a cute set of bright blue earlobes. Other members of this exclusive chicken club include the H’Mong chickens of Vietnam and the svarthöna of Sweden.
Scientists have been investigating the genes of this unique group of chickens to better understand exactly what causes their unusual colouring. Using DNA sequencing technology, a team at Uppsala university was able to show that fibromelanosis is caused by a genetic rearrangement. This is a type of mutation which happens when sections of the DNA become re-organised during replication. This shuffling of the genetic material results in changes in proteins, the molecular machines which are generated using DNA.
Now, back to our chickens. The gene which is altered in these jet-black birds is called Endothelin 3, or EDN3 for short. One of its functions is to control skin colour. It does this by causing the body to produce more melanoblasts, a type of pigmented cell which gives colour to hair or skin. These cells are also present in normal chickens, they are just limited to certain areas such as the feather follicles or outer skin. In Ayam Cemani and the other black chickens, almost all of the cells produce EDN3, meaning that up to 10 times more pigment cells are produced.
This explains why the inky-black colouring is not restricted to the skin of the chicken, but is also found in the organs, bones and flesh, creating a look that is either delicious or downright creepy depending on your point of view.
The mutation is so unusual that scientists believe it only occurred once. Meaning that all of the different breeds of black chicken are descendants of a single, very pigmented bird that lived a long time ago.
Origin of the Ayam Cemani breed
It’s difficult to say when this would have been exactly, but we do found have records indicating that Marco Polo had spotted Silkie chickens when he visited China before 1300. He spoke of them very highly, saying “You must know they have a kind of fowls which have no feathers, but hair only, like a cat’s fur. They are black all over; they lay eggs just like other fowls, and are very good to eat.” So, while we don’t know whether Mr Polo tried the Lamborghini of chickens, but we do know that he gave the Silkie the seal of approval.
Luckily, the genetic mutation causing the pigmentation of Ayam Cemani doesn’t cause any problems for the bird (apart from the fact that they are perceived as particularly tasty). It does, however, provide a great example of how genetic rearrangements can influence evolution.
Mutations like the one that cause fibromelanosis are found throughout the animal kingdom, and understanding how they work provides intriguing clues about how changes in DNA influence our physical traits.
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