The view that animals have become more complex over time could be a thing of the past, according to the latest research. The new evidence, from scientists at the University of St Andrews, suggests that some modern day animals may have evolved instead by becoming less complex. The researchers say that the discovery, of ghostly remains of gene neighbourhoods that once existed in a 550 million year old ancestor, suggests that the earliest animal was more complex than previously thought. The findings, published later today in the journal, Current Biology, appear to contradict the common perception of evolution – that creatures have advanced by becoming genetically more complex over time.
Researchers, led by Dr David Ferrier of The Scottish Oceans Institute at the University of St Andrews, found that some modern-day animals like sponges, comb jellies and placozoans (a flat, splodge of an animal with no head, tail, gut or limbs) may have actually evolved by losing some genes and perhaps became simplified from a more complex ancestor, from which the entire animal kingdom evolved. Dr Ferrier and his team studied key genes, known as Hox and ParaHox, which are renowned for building the bodies of nearly all modern-day animals. They control where ribs develop in humans or where wings develop in flies, and can be disrupted in diseases such as cancer and diabetes.
Until this latest research, scientists had argued over whether these genes evolved in a step-wise fashion, during early animal evolution, or instead were present in the very first animals. Via Research suggests that evolution sometimes meant becoming simpler, not more complex.