The Tree of Life’s First Branch

There was one common ancestor for all animals on Earth. If you trace the history of any creature—from humans to slugs—you’d eventually follow all the branches of the animal tree of life back to its trunk.

Coming from the other direction, that trunk had to branch off at some point, or we wouldn’t have a diverse collection of animals. Unfortunately, that first split has been elusive to scientists because it took place around 600 million years ago.

Scientists have figured out that the first split resulted in the birth of two creatures. One was the ancestor of almost all animals, while its “sister” gave rise to just one group of modern animals.

For decades, scientists have debated which group of animals came from the “sister” ancestor. They had two contenders—sea sponges and comb jellies. Thanks to new methods that enable researchers to analyze these animals’ chromosomes, they think they have the answer.

The key was to look not just at what genes each animal had, but where those genes were located on the chromosomes. As a creature evolves, chromosomes will rearrange, and genes will move around. But once genes move, it’s almost impossible for them to return to their original position. Therefore, whichever animal showed the least re-shuffling of genes on its chromosomes must have come into existence first. Out of the two options, whichever animal has the least shuffling is the sister.

The team compared the placements of certain groups of genes in sponges and comb jellies to the placements of those same groups in their closest single-cell non-animal relatives. (The single-cell relatives would have been closely related to the “trunk” organism and would have evidence of what that original genome looked like.) The closer an organism is to that genome, the less it has changed, and the more likely it is the sister.

In both the non-animals and the comb jellies, they found 14 groups of genes located on separate chromosomes. But in the sponges, they found those 14 groups were rearranged into 7 groups, which indicated they split from the original genome later than the comb jellies.

Consequently, the sister to all other animals, the first to branch off, and the most genetically isolated animal is the comb jelly.

Besides answering a long-standing biological question, scientists can investigate what this knowledge tells us about animal evolution, and the mechanisms of that evolution. And so the search for more answers continues.

Thank goodness they figured that out. I don’t think I could have remained sane another day without knowing which animal came first.

 

https://www.msn.com/en-us/news/technology/scientists-have-found-the-first-branch-on-the-tree-of-life/ar-AA1LAkS2?ocid=hpmsn&cvid=cddbc1e105374c51afa382b8cdd3674d&ei=18

1600 Year Old Churches in Egypt

Archaeologists have found two 1,600-year-old churches in Egypt’s western desert. This discovery offers rare evidence of Christianity’s rise in Egyptian desert settlements.

The churches were found at Kharga Oasis, an ancient settlement roughly 350 miles southwest of Cairo. The Christian remains include cemeteries, churches, and a mural of Jesus curing a sick man, but the Oasis has been inhabited since antiquity, thanks to underground water sources.

The archaeologists uncovered the remains of an entire settlement at Kharga Oasis, including multiple residential buildings made of mudbrick, with some walls still retaining plaster. The team also found ovens and large clay jars that were set into the ground to store food. Other finds included inscribed pottery shards, vessels, glass and stone pieces, and several burials.

However, the centerpiece of the excavation was the discovery of two churches. Both date back to the early Coptic era, which is Egypt’s Christianization period that began in the 4^th century AD.

One church was a grand basilica made of mudbrick. It held remnants of a large hall and two aisles.

The second church was smaller. It had a rectangular layout and was surrounded by the remains of seven external columns. Some of its inner walls were decorated with Coptic inscriptions. The remains of service buildings were found to the west of the smaller church.

This discovery sheds light on the beginnings of the Coptic period in Egypt. It also shows the importance of Egypt’s western oases as centers of religious and social life in various eras. It highlights the tolerance and cultural and religious diversity of Egyptian civilization.

 

https://www.msn.com/en-us/news/world/archaeologists-find-1-600-year-old-churches-and-mural-of-jesus-in-egyptian-desert-settlement/ar-AA1LAKXW?ocid=hpmsn&cvid=9cfbbedf980846debce3c660196a3d2e&ei=61