List of examples of convergent evolution


Convergent evolution—the repeated evolution of similar traits in multiple lineages which all ancestrally lack the trait—is rife in nature, as illustrated by the examples below. The ultimate cause of convergence is usually a similar evolutionary biome, as similar environments will select for similar traits in any species occupying the same ecological niche, even if those species are only distantly related. In the case of cryptic species, it can create species which are only distinguishable by analysing their genetics. Distantly related organisms often develop analogous structures by adapting to similar environments.

In animals

Mammals

Prehistoric reptiles

Extant reptiles

Avian

Fish

Amphibians

Arthropods

Molluscs

Other

In plants

In fungi

In proteins, enzymes and biochemical pathways

Functional convergence

Here is a list of examples in which unrelated proteins have similar functions with different structure.
  • The convergent orientation of the catalytic triad in the active site of serine and cysteine proteases independently in over 20 enzyme superfamilies.
  • The use of an N-terminal threonine for proteolysis.
  • The existence of distinct families of carbonic anhydrase is believed to illustrate convergent evolution.
  • The use of -7-dodecen-1-yl acetate as a sex pheromone by the Asian elephant and by more than 100 species of Lepidoptera.
  • The biosynthesis of plant hormones such as gibberellin and abscisic acid by different biochemical pathways in plants and fungi.
  • The protein prestin that drives the cochlea amplifier and confers high auditory sensitivity in mammals, shows numerous convergent amino acid replacements in bats and dolphins, both of which have independently evolved high frequency hearing for echolocation. This same signature of convergence has also been found in other genes expressed in the mammalian cochlea
  • The repeated independent evolution of nylonase in two different strains of Flavobacterium and one strain of Pseudomonas.
  • The myoglobin from the abalone Sulculus diversicolor has a different structure from normal myoglobin but serves a similar function — binding oxygen reversibly. "The molecular weight of Sulculus myoglobin is 41kD, 2.5 times larger than other myoglobins." Moreover, its amino acid sequence has no homology with other invertebrate myoglobins or with hemoglobins, but is 35% homologous with human indoleamine dioxygenase (IDO), a vertebrate tryptophan-degrading enzyme. It does not share similar function with IDO. "The IDO-like myoglobin is unexpectedly widely distributed among gastropodic molluscs, such as Sulculus, Nordotis, Battilus, Omphalius and Chlorostoma."
  • The hemocyanin from arthropods and molluscs evolved from different ancestors, tyrosinase and insect storage proteins, respectively. They have different molecular weight and structure. However, the proteins both use copper binding sites to transport oxygen.
  • The hexokinase, ribokinase, and galactokinase families of sugar kinases have similar enzymatic functions of sugar phosphorylation, but they evolved from three distinct nonhomologous families since they all have distinct three-dimensional folding and their conserved sequence patterns are strikingly different.
  • Hemoglobins in jawed vertebrates and jawless fish evolved independently. The oxygen-binding hemoglobins of jawless fish evolved from an ancestor of cytoglobin which has no oxygen transport function and is expressed in fibroblast cells.
  • Toxic agent, serine protease BLTX, in the venom produced by two distinct species, the North American short-tailed shrew and the Mexican beaded lizard, undergo convergent evolution. Although their structures are similar, it turns out that they increased the enzyme activity and toxicity through different way of structure changes. These changes are not found in the other non-venomous reptiles or mammals.
  • Another toxin BgK, a K+ channel-blocking toxin from the sea anemone Bunodosoma granulifera and scorpions adopt distinct scaffolds and unrelated structures, however, they have similar functions.
  • Antifreeze proteins are a perfect example of convergent evolution. Different small proteins with a flat surface which is rich in threonine from different organisms are selected to bind to the surface of ice crystals. "These include two proteins from fish, the ocean pout and the winter flounder, and three very active proteins from insects, the yellow mealworm beetle, the spruce budworm moth, and the snow flea."
  • RNA-binding proteins which contain RNA-binding domain and the cold-shock domain protein family are also an example of convergent evolution. Except that they both have conserved RNP motifs, other protein sequence are totally different. However, they have a similar function.
  • Blue-light-receptive cryptochrome expressed in the sponge eyes likely evolved convergently in the absence of opsins and nervous systems. The fully sequenced genome of Amphimedon queenslandica, a demosponge larvae, lacks one vital visual component: opsin-a gene for a light-sensitive opsin pigment which is essential for vision in other animals.
  • The structure of immunoglobulin G-binding bacterial proteins A and H do not contain any sequences homologous to the constant repeats of IgG antibodies, but they have similar functions. Both protein G, A, H are inhibited in the interactions with IgG antibodies by a synthetic peptide corresponding to an 11-amino-acid-long sequence in the COOH-terminal region of the repeats.
  • The evolution of cardiotonic steroid resistance via amino acid substitutions at well-defined positions of the Na+,K+-ATPase α-subunit in multiple insect species spanning 6 orders.

Structural convergence

Here is a list of examples in which unrelated proteins have similar tertiary structures but different functions. Whole protein structural convergence is not thought to occur but some convergence of pockets and secondary structural elements have been documented.
  • Some secondary structure convergence occurs due to some residues favouring being in α-helix and for hydrophobic patches or pocket to be formed at the ends of the parallel sheets.
  • is a database of convergently evolved protein interaction interfaces. Examples comprise fibronectin/long chain cytokines, NEF/SH2, cyclophilin/capsid proteins.

Mutational convergence

The most well-studied example is the Spike protein of SARS-CoV-2, which independently evolved at the same positions regardless of the underlying sublineage. The most eminent examples from the pre-[SARS-CoV-2 SARS-CoV-2 Omicron variant|Omicron variant|Omicron] era were E484K and N501Y, while in the Omicron era examples include R493Q, R346X, N444X, L452X, N460X, F486X, and F490X.