[5] Mosses share fundamental genetic and physiological processes with vascular plants, although the two lineages diverged early in land-plant evolution.

[citation needed] The targeted deletion or alteration of moss genes relies on the integration of a short DNA strand at a defined position in the genome of the host cell.

[11] The first study using knockout moss appeared in 1998 and functionally identified ftsZ as a pivotal gene for the division of an organelle in a eukaryote.

[14] By multiple gene knockout Physcomitrella plants were engineered that lack plant-specific post-translational protein glycosylation.

[8][16] Physcomitrella ecotypes, mutants, and transgenics are stored and made freely available to the scientific community by the International Moss Stock Center (IMSC).

[17] A spore develops into a filamentous structure called protonema, composed of two types of cells – chloronema with large and numerous chloroplasts and caulonema with very fast growth.

The resulting diploid zygote develops into a sporophyte composed of a foot, seta, and capsule, where thousands of haploid spores are produced by meiosis.

The genome sequence of P. patens has revealed the presence of numerous genes that encode proteins necessary for repair of DNA damages by homologous recombination and by other pathways.

[20] Loss of PpRAD51 causes marked hypersensitivity to the double-strand break-inducing agent bleomycin, indicating that homologous recombination is used for repair of somatic cell DNA damages.