Sperm and egg cells, or gametes, are unusual. Egg cells are some of the largest cell types, and sperm are some of the smallest. In humans, these haploid cells come together to form diploid cells. It's ...

A study from Karolinska Institutet in Sweden, among others, presents the theory that egg-sperm fusion, a crucial feature of sexual reproduction in plants and animals, may have originated from an ...

While mutation and sexual reproduction drive genetic innovation in many eukaryotes, for life’s exclusively unicellular domains—archaea and bacteria—horizontal gene transfer is a critical mechanism for ...

Asgard archaea, proposed as a new archaeal superphylum, are currently composed of five phyla Lokiarchaeota, Thorarchaeota, Odinarchaeota, Heimdallarchaeota, and Helarchaeota. Since Asgard archaea ...

The origin of the eukaryotic cell is considered one of the major evolutionary transitions in the history of life. Current evidence strongly supports a scenario of eukaryotic origin in which two ...