Study Finds Plant Reproducing Sexually Produces Cloned Offspring
Research has identified the first known sexually reproducing species where no genetic recombination occurs during gamete formation.
Scientists at the Max Planck Institute for Plant Breeding Research in Germany have identified the Brazilian plant Rhynchospora tenuis, which reproduces sexually and produces seeds, but where the genetic material does not recombine in the offspring. This is the first documented case of sexual reproduction completely lacking genetic recombination in both sexes.
Sexual reproduction typically involves meiosis, a process where DNA exchange occurs between chromosomes to generate genetic diversity. However, in this plant species, no DNA exchange happens between the parent chromosomes during meiosis. Instead, the offspring are genetically identical to the mother plant, akin to cloning.
The research team combined genome assembly, chromosome imaging, and DNA sequencing of individual pollen nuclei. Their analysis of over 10,000 pollen nuclei revealed no recombination events, and there was no evidence of chromosome exchange in the female reproductive pathway either.
The plant's unusual reproductive strategy is linked to its low chromosome count (only two chromosomes in its haploid form) and its holocentric chromosomes. Furthermore, the plant employs "reverse meiosis," where sister chromatids separate before homologous chromosomes. This atypical mechanism, coupled with strong selection during seed development, enables the production of genetically identical offspring.