Decades-old question surrounding the start of the tree of life could finally be solved

After decades of debate, scientists believe they have identified the most recent ancestor of the sister to all animals via the novel use of an analytical technique. The finding settles a central question about the evolution of the entire tree of animal life. 
All animal life is descended from a single common ancestor — a multicellular organism that most likely lived more than 600 million years ago. This ancestor had two offspring; one that led to the evolution of all animal life, and another that is referred to as the sister to all animals.
In the quest to identify which living animals are most closely related to this sister group, scientists have narrowed down the possibilities to two candidates: sea sponges and comb jellies (ctenophores). Conclusive evidence to support either candidate, however, has remained elusive. 
Now, a new study published May 17 in the journal Nature has resolved this long-running debate with the novel use of chromosomal analysis.
The solution came while Darrin T Schultz, lead author and current postdoctoral researcher at the University of Vienna, and a multi-institutional team were sequencing the genomes (the complete set of genetic information) of comb jellies and their close relatives to understand more about their evolution.
Decades-old question surrounding the start of the tree of life could finally be solved