A recent study published in Nature reveals that comb jellies, or ctenophores, are the earliest lineage to diverge from the animal tree of life, followed by sponges. This conclusion was reached using a novel chromosome-based approach, resolving longstanding debates stemming from inconclusive gene sequence studies. Understanding these early lineages is crucial for insights into the evolution of fundamental biological features such as the nervous system and digestive tract.
Researchers analyzed the chromosome structures of various species, determining that ctenophores share similar gene distributions with non-animal organisms, indicating they branched off earlier than sponges. This research enables a deeper understanding of the origins of animal life, dating back to 600-700 million years ago, and offers context for the development of essential animal traits.
Additionally, this study enhances knowledge surrounding the evolutionary relationships among diverse animal lineages, suggesting that many features defining bilaterian animals evolved later in the evolutionary timeline. With these advancements in genomic understanding, scientists are now better equipped to explore the foundational aspects of animal biology, shedding light on how complex life forms we see today emerged from simpler ancestors.
