Washington: A new research has revealed that the closest relatives to land plants are actually conjugating green algae such as Spirogyra.
It was thought that Charales were the closest relatives to land plants because they share (amongst other characteristics) a similar method of fertilisation, oogamy, with a large egg and small swimming sperm.
Some phylogenetic analysis had been done previously, on a smaller number of genes, which seemed to support the Charales theory.
However, a multinational team, involving researchers in Germany and Canada, analysed genetic divergence in 129 genes from 40 different green plant taxa. This data showed that, despite the differences in reproductive strategy, the closest living relatives to land plants are in fact the Zygnematales.
Co-author of the study, Burkhard Becker explained, "It seems that Zygnematales have lost oogamy and their ability to produce sperm and egg cells, and instead, possibly due to selection pressure in the absence of free water, use conjugation for reproduction.”
The research has been published in BioMed Central``s open access journal BMC Evolutionary Biology.