Alan Wilson and colleagues in 1987 famously showed that the amino acid sequence of lysozyme had converged to be the same in the cow and in a leaf-eating monkey, so that molecular phylogeny based on this protein would have erroneously placed these unrelated, phytophagous, mammals on the same branch of the tree. Since DNA evolution is actually less constrained than amino acid sequence (because of “third base wobble etc”), one might expect that there are now many examples of DNA convergence as well.
1. One general example involves the fact that guanine is more sensitive to oxidation than the other three bases. 8-oxoguanine, the product of its oxidation, is read by error-correcting enzymes as adenine, leading to an inexorable AT bias in mammalian DNA, that is greatest in mammals that have the highest metabolism.
2. The slime mould, Dictyostelium, has a large AT bias which results in its alignment with procaryotes that have a similar bias. Without human help, computers align the slime mould DNA with the bacterial DNA. This erroneous pairing disappears if translated codons are used for phylogeny instead of DNA, when the slime mould moves a number of nodes up the tree of lie to join the fungi.
3. Both microbats and megabats have dramatically enlarged immune systems, an evolutionary response that is thought to relate to an increased need to repair damage to cells caused by the very high level of ROS (Reactive Oxygen Species) that are produced in powered flight when metabolic rate increases by 20X. This increased immunological competence is probably responsible for the tolerance of both kinds of bats to many kinds of virus that are lethal to humans such as Ebola, Marburg, Nypa, Hendra, Rabies, Sars, Mers, etc Molecular dissection of microbat and megabat immune systems shows that they have been enlarged by completely separate mechanisms, a striking example of molecular convergence at the DNA level.
1. One general example involves the fact that guanine is more sensitive to oxidation than the other three bases. 8-oxoguanine, the product of its oxidation, is read by error-correcting enzymes as adenine, leading to an inexorable AT bias in mammalian DNA, that is greatest in mammals that have the highest metabolism.
2. The slime mould, Dictyostelium, has a large AT bias which results in its alignment with procaryotes that have a similar bias. Without human help, computers align the slime mould DNA with the bacterial DNA. This erroneous pairing disappears if translated codons are used for phylogeny instead of DNA, when the slime mould moves a number of nodes up the tree of lie to join the fungi.
3. Both microbats and megabats have dramatically enlarged immune systems, an evolutionary response that is thought to relate to an increased need to repair damage to cells caused by the very high level of ROS (Reactive Oxygen Species) that are produced in powered flight when metabolic rate increases by 20X. This increased immunological competence is probably responsible for the tolerance of both kinds of bats to many kinds of virus that are lethal to humans such as Ebola, Marburg, Nypa, Hendra, Rabies, Sars, Mers, etc Molecular dissection of microbat and megabat immune systems shows that they have been enlarged by completely separate mechanisms, a striking example of molecular convergence at the DNA level.
Are visual proteins like opsin convergent or a shared molecular synapomorphy from bacteria through multicellular animals?
Visual pigments are notoriously plastic and can change their spectral sensitivity quickly in the face of changes in spectral properties of the environment. A striking example is found in Lake Baikal, where fish living at different depths with different spectral environments have matching visual pigments. So one would expect convergent fine tuning of sequence responsible for spectral sensitivity while at the same time appreciating the deep divergences that provide links to the origins of the visual pigments in ancient taxa, such as those in bacteria.
The duplication of the LWS and MWS opsin genes in some primates occurred many millions of years ago, however, their introns are almost identical (indeed many of them are 100% identical) - thus the DNA sequences have undergone convergent evolution.
The occurrence of any of the new types of organisms is the divergence of the total DNA in different lines of evolution. For example, Sandpiper (bird) give two different forms - live in meadows (lapwing) and aquatic (herbalist).
There were multiple converGences on C4 photosynthetic pathways across angiosperms
Not sequence but composition and GC/AT - skew convergence can be observed in mitochondrial genome when studying large phylogenies. Mitochondrial genome consists of two strands (heavy and light) that possess different number of G and C nucleotides respectively. This, in turn influence the patterns of amino asid substitutions and in it extreme form can even lead to homoplasy when skew in nucleotide content causes particular restriction in the amino acid composition.
Please consider this one:
Article A comprehensive analysis of bilateran mitochondrial genomes ...
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