Selective breeding over the past century has given German pigs short and flat noses. These changes, although not intentional selection for traits, may be influenced by diet and are the result of breeding to promote growth and increase fecundity. The study highlights how humans are accelerating evolution faster than previously thought.
Short snout and flat profile - In just 100 years, humans have dramatically changed the shape of the German pig's skull. According to a research team from the Martin Luther University (MLU) in Halle-Wittenberg, this change was most likely caused by new breeding methods introduced at the beginning of the 20th century. Their research, published in the journal Royal Society Open Science, is based on an analysis of 3D scans of 135 wild boar and domestic pig skulls from the early 20th and 21st centuries. Surprisingly, similar changes were observed even in species housed separately.
Pigs have been raised as livestock by humans for centuries, and during that time, pigs have undergone significant transformations. For example, the pigs grew larger, lost their black and brown bristles, and became darker.
"Demand for pork increased significantly in Germany at the beginning of the 20th century, so breeders were encouraged to optimize their livestock. They needed animals that grew quickly, had good meat quality, and were highly fertile," explains Dr. Renate Schafberg, Director of the MLU Livestock Collection. In the current study, she and Dr. Ashleigh Haruda of the University of Oxford analyzed 135 skulls from three different species: some from the early 20th century and some only a few years old. The skulls are either from the early 20th century or are only a few years old.
Two domestic pig breeds have undergone significant changes: the animals' snouts have become significantly shorter and flatter, and the skulls of more modern animals no longer have a slightly outward-curving forehead. "We did not expect such clear differences to emerge in just 100 years," Schafberg said. "It is noteworthy that the two species of domestic pigs underwent identical changes despite being raised separately. These changes occurred even though breeders were not specifically selecting for the animals' skull shape because this trait is not important for breeding. Instead, these changes appear to be an unintentional by-product of selection for desirable traits."
Another reason for these changes may be related to changes in the animals' diets. Nutrition is known to affect animal growth and development. Today, pigs mainly eat high-protein pellet feed. In contrast, the skulls of wild boars, which are still omnivores, show no such changes.
"These findings show how much influence humans have had on animal evolution." Charles Darwin believed that major changes took a long time to occur - millions of years. Our work provides further evidence that humans can greatly speed up this process through selective breeding.
Compiled from /ScitechDaily