Researchers have produced the first complete genome assemblies for two animal species widely used in scientific research: the marmoset and the zebra finch. The marmoset, a tiny South American monkey, is an important model for studying human diseases. Its new genome provides a complete baseline for understanding the primate's DNA, enabling research into Alzheimer's and other neurodegenerative diseases. The zebra finch, one of the best-studied songbirds, is a model for understanding the biology and neuroscience of vocal learning. Its complete genome has exposed thousands of previously hidden genes and chromosome structures, offering new insights into vocal learning. These genome maps give scientists detailed reference points to study gene changes and functions in both species.