The study by Henriques et al. investigates the evolutionary trajectories and functional potential of capsid (CA) genes derived from *Metaviridae*, a lineage of retrovirus-like retrotransposons, in mammals. Using a complete human genome assembly and additional vertebrate genomes, the authors re-analyze the domestication events of these genes, finding at least five independent domestication events from diverse *Metaviridae* lineages. These events have led to three universally retained single-copy genes under purifying selection and two gene families unique to placental mammals, with evidence of rapid evolution in some members. The study reveals diverse amino-terminal domains in the SIRH/RTL family, widespread loss of protein-coding capacity in RTL10, and differential utilization of an ancient programmed ribosomal frameshift in RTL3. Additionally, most members of the PNMA family encode a conserved putative RNA-binding domain, which is also present in some *Metaviridae*. The findings correct previous annotations of the essential CDC8 gene and highlight the divergent outcomes of multiple domestication events from diverse *Metaviridae* in the common ancestor of placental mammals.The study by Henriques et al. investigates the evolutionary trajectories and functional potential of capsid (CA) genes derived from *Metaviridae*, a lineage of retrovirus-like retrotransposons, in mammals. Using a complete human genome assembly and additional vertebrate genomes, the authors re-analyze the domestication events of these genes, finding at least five independent domestication events from diverse *Metaviridae* lineages. These events have led to three universally retained single-copy genes under purifying selection and two gene families unique to placental mammals, with evidence of rapid evolution in some members. The study reveals diverse amino-terminal domains in the SIRH/RTL family, widespread loss of protein-coding capacity in RTL10, and differential utilization of an ancient programmed ribosomal frameshift in RTL3. Additionally, most members of the PNMA family encode a conserved putative RNA-binding domain, which is also present in some *Metaviridae*. The findings correct previous annotations of the essential CDC8 gene and highlight the divergent outcomes of multiple domestication events from diverse *Metaviridae* in the common ancestor of placental mammals.