What did the first living thing look like? Where did it live? Some biologists think that by using DN
What did the first living thing look like? Where did it live? Some biologists think that by using DNA sequencing, we can construct an evolutionary family tree through the past to get a pretty good idea.This first life form is referred to as LUCA, the Last Universal Common Ancestor: a single-cell organism similar to a bacterium that lived about four billion years ago. From this one organism evolved all plants, animals, bacteria, and archaea. A team of evolutionary biologists led by William F. Martin of Heinrich University used DNA sequencing of bacteria and archaea in order to arrange the protein-coding genes in an evolutionary family tree. This narrowed the possible genes that could have originated in LUCA from about six million to just 335. These genes (including one that metabolizes hydrogen and another that produces an enzyme in microbes living in extremely high temperatures) suggest that LUCA lived in the extreme conditions of deep-sea vents, surrounded by gasses, metal, and heat.Martin and his team have used their findings to suggest that these magma-filled vents are where life originated. However, many biologists remain skeptical that this discovery is anything more than just an interesting find. Dr. John Sutherland of the University of Cambridge says that the team has no proof that life originated in the deep-sea vents that necessitated these proteins, and that Dr. Martin’s finding “has nothing to do with the actual origin of life.” Sutherland looks towards other methods, such as chemical experiments that trigger light reactions in certain environments, to get an idea of what conditions first created life.Read more here. -- source link
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