An international team of experts reported in The Proceedings of the National
Academy of Sciences (PNAS) that ferns got their gene for sensing light from
another plant called hornwort through horizontal gene transfer. According to
the researchers, ferns encountered an evolutionary burst about 100 years ago
and thus 80 percent of present fern species can be traced to that
occurrence. These species developed a light-sensing protein called
neochrome, which makes ferns sensitive to dim levels of light. Thus, ferns
thrive even on low light intensity in shady forest floors.

Mr. Fey-Wei Li of Duke University examined the history of the light-sensing
gene in ferns. However, he did not find any gene similar to neochrome gene
until scientists at the University of Alberta released a new database of DNA
of several plant species. Using the database, he searched for a
neochrome-like gene and found one not in fern but in hornwort, a moss-like
primitive plant.

Mr. Li hypothesized that the transfer happened between a hornwort and a fern
growing in close contact. Once a fern picked up the neochrome gene, his
research indicates, it moved into other fern species as well. Dr. Jeffrey
Palmer, an evolutionary biologist from Indiana University, confirmed that
several evidences have been found on genes moving between plant species and
he expects that more cases will be revealed by scientists in the coming
years.

[www.pnas.org]