Why do animals have dead ears?

Usually, domesticated animals become close to humans often have similar mutations, including dead ears.

Russian geneticist Dmitry Belyaev from the late 1950s set up a long-term experiment that lasted up to 20 generations for silver-haired foxes to find out if he could remove the wild nature from the species. This report is good or not.

For about 25 years, he and his successor, Lyudmilla Trut, created a line of silver foxes that was sufficiently pure to be considered human pets.

For those who study evolution, this is an extremely short period of time. But this time is enough to see that the next generation of this fox has a change from their original breed: the face is shorter, the teeth are smaller, the ears are softer and more downward, the tail is more pointed. and the coat has a change in color.

Domesticated animals have increasingly different characteristics from their wild ancestors.

Clearly, domesticated animals gather quite consistently differences with their wild ancestors. And that phenomenon is called 'pure syndrome'.

Explaining more about this phenomenon, Adam Wilkins, from the Stellenbosch Advanced Research Institute of South Africa and colleagues, hypothesized that the 'pure syndrome' is due to the development of accompanying neural crest cells. with the development of animal bodies.

Neural crest cells (also known as Zwischenstrang) are important organ systems in developing embryos.

Neurological crest is a cell layer located in the epidermis, separating two parts of the skin production and the central nervous system production unit. These cells work by moving into the mesoderm, which is the place to produce bone, connective, muscular, gland and reproductive tissue.

This type of cell not only produces tissue on the facial bones, teeth and outer ears but also produces pigment cells, nerves and adrenal glands. It also plays a very important role in promoting the development of parts of the brain before and in many endocrine glands.

The researchers suggest that it is the domestication process that selects pre-existing variants in some genes that affect the development of neural crest cells. This reduces the number and activity of nerve cells. It also affects a variety of structures derived from neural crest, leading to 'pure syndrome'.

This hypothesis partially answers the research question. However, they still need many other experiments to test the results and make other theories.