The evolutionary history of eukaryotes: how the ancestral proto-lineage conserved in hypoxic eukaryotes led to protist pathogenicity

Introduction Until recently, the evolutionary origin of stemness was largely unknown [1]. The central question has remained the same: did stem cells originate as single-celled organisms or not? [2]. It was Ernst Haeckel, 145 years ago, who first considered singlecelled organisms as the phylogenetic ancestors of multi-celled organisms [3]. However, until