The moss Physcomitrella patens is an attractive model system for plant biology and functional genome analysis.(1-7) It shares many biological features with higher plants (vascular plants) but has the unique advantage of an efficient homologous recombination system for its nuclear DNA.(2,3) This allows precise genetic manipulations and targeted knockouts to study gene function, an approach that due to the very low frequency of targeted recombination events is not routinely possible in any higher plant.(3) Mosses are situated under the division Bryophyta which are non vascular plants, lacking true stems, seeds, leaves and roots as compared to Tracheophytes, (vascular plants) which contain xylem and phloem.(1) Mosses are one of the oldest groups
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(7) Therefore P. patens is a model organism in the studies of DNA repair as well. Stefan A Rensing and his fellow coworkers reported a draft genome sequence of the model moss Physcomitrella patens and compared its features with those of flowering plants, from which it is separated by more than 400 million years, and unicellular aquatic algae. This comparison revealed genomic changes naturally associated with the evolutionary movement to land, including a general increase in gene family complexity; loss of genes associated with aquatic environments (e.g., flagellar arms); acquisition of genes for tolerating terrestrial stresses (e.g., variation in temperature and water availability); and the development of the auxin and abscisic acid signaling pathways for coordinating multicellular growth and dehydration response. The Physcomitrella genome provided a resource for phylogenetic inferences about gene function and for experimental analysis of plant processes through this plant's unique facility for reverse genetics.
(7) Therefore P. patens is a model organism in the studies of DNA repair as well. Stefan A Rensing and his fellow coworkers reported a draft genome sequence of the model moss Physcomitrella patens and compared its features with those of flowering plants, from which it is separated by more than 400 million years, and unicellular aquatic algae. This comparison revealed genomic changes naturally associated with the evolutionary movement to land, including a general increase in gene family complexity; loss of genes associated with aquatic environments (e.g., flagellar arms); acquisition of genes for tolerating terrestrial stresses (e.g., variation in temperature and water availability); and the development of the auxin and abscisic acid signaling pathways for coordinating multicellular growth and dehydration response. The Physcomitrella genome provided a resource for phylogenetic inferences about gene function and for experimental analysis of plant processes through this plant's unique facility for reverse genetics.