Editing Convergent evolution (section)

=== Carnivory ===
[[File:Chitinase4TC.jpg|thumb|upright=1.5|Molecular convergence in [[carnivorous plant]]s]]

[[Carnivorous plant|Carnivory]] has evolved multiple times independently in plants in widely separated groups. In three species studied, ''[[Cephalotus|Cephalotus follicularis]]'', ''[[Nepenthes alata]]'' and ''[[Sarracenia purpurea]]'', there has been convergence at the molecular level. Carnivorous plants secrete [[enzymes]] into the digestive fluid they produce. By studying [[Purple acid phosphatases|phosphatase]], [[Glycoside hydrolase family 19|glycoside hydrolase]], [[glucanase]], [[RNASET2|RNAse]] and [[chitinase]] [[enzyme]]s as well as a [[pathogenesis-related protein]] and a [[thaumatin]]-related protein,  the authors found many convergent [[amino acid]] substitutions. These changes were not at the enzymes' catalytic sites, but rather on the exposed surfaces of the proteins, where they might interact with other components of the cell or the digestive fluid. The authors also found that [[homologous gene]]s in the non-carnivorous plant ''[[Arabidopsis thaliana]]'' tend to have their expression increased when the plant is stressed, leading the authors to suggest that stress-responsive proteins have often been co-opted{{efn|The prior existence of suitable structures has been called [[pre-adaptation]] or [[exaptation]].}} in the repeated evolution of carnivory.<ref name=Fukushima2017>{{cite journal |last1=Fukushima |first1=K |last2=Fang |first2=X |display-authors=etal |title=Genome of the pitcher plant Cephalotus reveals genetic changes associated with carnivory |journal=Nature Ecology & Evolution |date=2017 |volume=1 |issue=3 |doi=10.1038/s41559-016-0059 |pmid=28812732 |doi-access=free |page=0059|bibcode=2017NatEE...1...59F }}</ref>