Bacterium still present in today's cells
By Robert Sanders, UC Berkeley Media Relations
Long before Earth became lush, when life consisted of single-celled organisms afloat in a planet-wide sea, bacteria invaded the ancient ancestors of plants and animals and took up permanent residence. One bacterium eventually became the mitochondria that today power all plant and animal cells; another became the chloroplast that turns sunlight into energy in green plants.
A new analysis by two University of California, Berkeley, graduate students more precisely pinpoints when these life-changing invasions occurred, placing the origin of photosynthesis in plants hundreds of millions of years earlier than once thought.
“When you are talking about these really ancient events, scientists have estimated numbers that are all over the board,” said coauthor Patrick Shih, a graduate student in the Department of Plant & Microbial Biology. Estimates of the age of eukaryotes – cells with a nucleus that evolved into all of today’s plants and animals – range from 800 million years ago to 3 billion years ago.