New DNA technology makes us 'redraw' the evolutionary tree

If you find yourself physically different from your blood relatives, you must have felt isolated from your family in some way. If you were a child, at certain moments of your life, you might even think of it as a sign that you were adopted.

And new research by biologists shows that appearance is like "deception moonlight" when it comes to the family aspect. New DNA technologies have shaken the family tree of many plants and animals. For example, primates, which include humans, were once thought to be close relatives of bats because of some similarities in their skeletons and brains. However, the latest DNA data classifies us as a group of rodents such as mice and rabbits. More surprisingly, bats turned out to be closely related to cows, horses and even rhinos. It sounds wrong!

Scientists in Darwin's day and for much of the 20th century could only find the evolutionary branches of life, by examining the structure and appearance of plants and animals. Life forms, grouped by similarities, are thought to have evolved together. About three decades ago, researchers started using DNA data to build "molecular trees". Many of the first trees based on the new DNA data showed the opposite of the classical trees.

New DNA technology has shaken the family tree of many plants and animals.

Sloths, anteaters, pangolins, shelled mammals, and nightingales were once thought to belong to the same group called edentates ("toothless"), because they share similar anatomical aspects. The molecular tree shows that these traits evolved independently in different branches of the mammalian evolutionary tree. It also turns out that aardvarks - the earth pig - are more closely related to elephants, while pangolins are more closely related to cats and dogs.

There is another important piece of evidence familiar to Darwin and his contemporaries. Darwin noted that the animals and plants that seem to share the closest common ancestor are often found geographically close together. The habitat of species is another strong indicator that they are related: species that live close together are more likely to share a family tree.

A recent study cross-referenced the location, DNA data, and appearance of a wide range of plant and animal species. Scientists looked at evolutionary trees based on the appearance or molecules of 48 groups of animals and plants, including bats, dogs, monkeys, lizards and pines. Evolution trees based on DNA data are two-thirds more likely to match a species' location than traditional evolutionary maps. In other words, the former trees show several species that are related to each other based on appearance. But new research shows they are far less likely to live in close proximity than species linked by DNA data.

Molecular trees of these colors are grouped better together than morphological trees, suggesting a closer association of molecules with biogeography.

It seems that evolutions are constantly inventing new solutions, almost without limits. Animals can look amazingly similar because they have evolved to do similar jobs or lead similar lifestyles. The extinct birds, bats, and pterosaurs had powerful wings for flight, but their ancestors all had forelimbs for walking on the ground.

Similar wing shapes and muscles evolved in different groups, because the physics of thrust and lift in the air were always the same. It's like the eyes of animals, which could have evolved 40 times in animals with just a few basic "designs". The human eye has much in common with the squid eye with a crystalline lens, iris, retina, and visual pigments. While squid are more closely related to snails, slugs and mussels than we are. Many of their mollusk relatives have only the simplest eyes.

The moles evolved into blind-eyed creatures, they are related to at least four species, on different continents and different branches of the mammalian branch of the evolutionary tree. For example, the Australian marsupial mole is more closely related to the kangaroo, the African golden mole is more closely related to the nightingale, the African groundhog (rodent) and the mole rat Europe and North America are more closely related to hedgehogs.all of which have evolved along a similar path.

Ernst Haeckel's evolutionary tree.

Until the advent of cheap and efficient gene-sequencing technology in the 21st century, the appearance of organisms was often all that evolutionary biologists had to do. While Darwin (1859) showed that all life on Earth is related to a single evolutionary tree, its branches are drawn rather elongated.

Anatomist Ernst Haeckel (1834-1919) was one of the first to draw evolutionary trees, in an attempt to show how major groups of life forms are related. Haeckel's drawings make amazing observations of living things that influenced art and design in the 19th and 20th centuries.

His family trees are based almost entirely on how those organisms look and develop as embryos. Many of his ideas about evolutionary relationships were preserved until recently. As it becomes easier and cheaper to collect and analyze large volumes of molecular data, more surprises await us.