Heart Evolution Atlas published in Science
On July 23, 2026, the large-scale scientific initiative "HEART" (Heart Evolution Atlas: a Repertoire across Tree-of-life), co-initiated by our laboratory and teams from renowned domestic and international research institutions, made significant progress. The research findings were published online in Science as a First Release under the title "Spatially resolved single-cell atlas reveals the macroevolutionary trajectory of animal hearts".
The heart is one of the key evolutionary innovations in the rise of complex animal life. For a long time, heart research has focused predominantly on a few model organisms such as zebrafish and mice, as well as humans, leaving much unknown about taxa that make up the vast majority of the animal kingdom, such as arthropods, mollusks, and protochordates. In fact, non-model animals occupy key evolutionary positions on the tree of life, carrying a rich array of transitional forms of the heart from simple tubular structures to complex chambered organs, while many taxa also possess astonishing cardiac regenerative capacities, making them uniquely valuable for research. However, constrained by numerous technical and methodological bottlenecks in the study of non-model species' hearts, fundamental questions concerning the cellular and molecular basis of heart diversity, its deep evolutionary origins, and the convergent and divergent evolutionary patterns across animal phyla remain unresolved up to date.
To overcome these limitations, the joint research team innovated and optimized technical methods to address related challenges, profiled adult hearts of 27 representative species of bilaterian animals, and integrated four types of data—comparative genomics, bulk transcriptomics, single-cell transcriptomics, and spatial transcriptomics—to construct a comprehensive molecular evolutionary atlas of the heart across the animal kingdom. The research scope spans the two major bilaterian lineages, protostomes and deuterostomes, encompassing the complete lineage of heart morphological evolution, covering various structural types including tubular (peristaltic and pulsatile), two-chambered, three-chambered, and four-chambered, with samples covering diverse ecological lifestyles, including aquatic, amphibious, and terrestrial. This study contributed the most extensive multidimensional transcriptome dataset of adult hearts to date in terms of species coverage and evolutionary span, and established the open-access database HEART (https://db.genomics.cn/stomics/heart/), providing important animal heart research resources and platform support for the entire scientific community.
The research reveals that the molecular blueprint of the animal "proto-heart" can be traced back to the bilaterian ancestor and follows a macroevolutionary strategy of "core gene repertoire → stepwise accretion". Cardiomyocytes, fibroblasts, endothelial cells, and neural cells are the four conserved cellular cornerstones of the bilaterian "proto-heart", and the genetic remodeling of cardiomyocytes is a key element for the animal heart to adapt to the transition from aquatic to terrestrial life. Based on the spatially resolved single-cell atlas, a class of cross-species conserved transient-state cardiomyocytes involved in responding to development, injury, or hypoxic stress was identified. Simultaneously, the conserved molecular signatures of atria and ventricles across protostomes and deuterostomes were systematically identified, and it was found that the molecular similarity between tubular heart cardiomyocytes and ventricular cardiomyocytes is stronger than the similarity with atrial cardiomyocytes in both major clades, proposing a new "ventricle-first, atrium-later" model of atrioventricular origin. This study not only provides original insights into understanding the macroevolutionary origins of the heart but also offers a valuable framework for deciphering the genetic regulation of the heart and for clinical research.
