What we most often fail to remember is that if it weren’t for algae, there would be no advanced life form on our planet, and today it turns out that this greenery is still closer to us than we think.
An oceanic explosion of algae some 650 million years ago gave rise to life on Earth as we know it today, and on top of that, it just turns out that those same algae may bring us answers to many questions about sex determination. Researchers at the University of Tokyo, as well as several other Japanese academic centers, have discovered that a green algae called Pleodorina starrii comes in three different genders: male, female, and bisexual (the name given by the research team). Such a species has never been discovered before: – It’s very unusual to find a species with three sexes, but under natural conditions it may not be that rare at all, explains one of the study’s authors, biologist Hisayoshi Nozaki.
It’s also worth noting that algae is not any specific scientific classification, but rather an informal term for a group traditionally consisting of several unrelated evolutionary lineages of tissueless organisms whose common features include autotrophism, or self-living, and a function as the primary producer of organic matter in water bodies. However, algae are not plants, as many people think, because they lack many of the typical characteristics and are not bacteria or fungi either. Additionally, they reproduce sexually as well as asexually depending on their life stage, and there are also bisexual species that can change sex depending on gene expression in the body, which theoretically gives a third sex, but with today’s hero P. starrii it is even different.
That’s because the bisexual form of P. starrii forms 32- or 64-cell colonies and has both male (small mobile) and female (large immobile) reproductive cells, so it doesn’t need to change specifically – the research team describes this as a completely unique system for algae. If the colonies are isolated from each other, the algae reproduce by division, producing copies of themselves, but if they are not isolated, the male cells are sent out into the world to find a female colony and create a new generation. However, it is much more interesting with bisexuals, which can form both male and female colonies and, what is more, combine with male, female and bisexual colonies. According to the scientists, this is a very exciting discovery, thanks to which we can learn more about the evolution of sexes, including humans and other animals, because three sexes usually means a transition process between two and one sex.