What an animal name that gives me milk

health : The milk mutation

Milk: the very word sounds like nutritious refreshment. What is just an opaque mixture of fat and water for some is the white elixir of life for others. As mother's milk, it is our very first food and, as cow's milk, it is an important nourishment for many people. Agriculture worldwide produces more than 500 million tons of milk per year.

By its very nature, milk is an extremely seasonal product. It is used exclusively for short-term nutrition for newborns. It was only thanks to targeted breeding that humans succeeded in training dairy cows for top performance over the millennia. Today robust cows give milk for five years, but high-performance cows usually “dry out” after three years. At the same time, the milk yield of an average German cow has risen continuously: In 1950 it was "only" 3831 liters, forty years later it was already 5908 liters. Milk march!

The source of baby food is the mammary organs or mothers. These mammary glands, which are arranged in pairs in mammals from the cow's udder to the breast of a woman, have arisen from skin glands that produce secretions and are transformed in a special way. The mammary gland and therefore milk in itself is unparalleled in the animal kingdom. The entire group of mammals rightly owes its name to these milk-producing mammary glands - the mammalia.

The following applies to all mammals: it's the mix that counts! Because a very special cocktail is mixed in the mammary glands. In addition to a lot of water, milk consists of fat, the protein casein and carbohydrates. Not all milk is created equal. Because milk has its own chemical composition for every type of mammal. But if the milk of other animal species is so chemically different, is it a good thing to drink this secretion, which was once specially produced for rearing boys, and as such a regular part of our diet?

Of all mammals, only humans have at some point started to consume milk even after the breastfeeding period. And only humans drink the milk of other animal species, especially beef cows. (Apart from the cat or the hedgehog, which we provide with a bowl of milk.)

Milk for adults: that sounds easier than it actually is. The milk sugar lactose, the most important carbohydrate in milk, plays a central role. Breast milk contains around five to seven percent, cow's milk five percent lactose. While babies are naturally equipped with the metabolic apparatus they need to break down lactose and break it down into galactose and glucose, many people lose this ability to a large extent at the age of four to five. From a chemical point of view, lactose is a rather bulky molecule that is sparingly soluble in water. In order to pass into the blood, it must first be broken down into its components galactose and glucose with the help of the carbohydrate-splitting enzyme lactase.

Researchers have long tried to find out when humans mutated into milk drinkers. Above all, it was puzzling how the unusual milk robbery came about, which turns alien species into wet nurses. Only recently, experts headed by Leena Peltonen from the University of Helsinki in Finland discovered that we make use of these animal nursing services thanks to a Stone Age invention of our genetic make-up. The first adult milk drinkers lived in the southern Urals about 6000 years ago, as molecular genetic studies in the journal "Science" (volume 306, page 1284) show.

To this end, more than 1,600 genetic material samples from 37 peoples from four continents were examined. According to this, the Kurgan in the area between the southern Urals and the Volga were the first nomadic shepherds to have the genetic change (mutation) that enables adults to digest milk. That means: splitting milk sugar. Although it happened by chance, this lactose tolerance was an advantage because the shepherds kept dairy cattle.

Subsequently, their gene spread with the migrations of humans 4500 to 3500 years ago in Europe; Today it is therefore mainly found among Indo-Europeans. Conversely, about half of humanity is lactose intolerant; after the end of breastfeeding she is no longer able to break down lactose without significant digestive problems.

Contrary to what has been assumed, the human consumption of cow's milk is apparently not directly related to the development of arable farming and agriculture around 12,000 years ago. Rather, it was probably only 6000 years ago for nomadic cattle herders in the southern Urals to preserve lactose-breaking enzymes for life - the “milk gene” for lactose tolerance.

Other researchers have found that in parallel with the spread of lactose tolerance, the targeted selection and breeding of those cows that gave a lot of milk began. Scientists working with Albano Beja-Pereira from the University of Grenoble recently discovered that the six most important genes for milk production are found in a particularly large number of variants in Nordic cow breeds alone, while there is no increased diversity in other genes.

So milk doesn't just perk up tired men. Perhaps it also helped mankind evolutionarily.

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