RE: The code that is DNA
December 24, 2019 at 5:18 pm
(This post was last modified: December 24, 2019 at 6:10 pm by John 6IX Breezy.)
(December 24, 2019 at 3:43 pm)Abaddon_ire Wrote: Guess what? It does not claim what John claims it says.
We can break down my statement and see how it is represented by the source:
"Homoplasy (such as convergence or reversals) often breaks with this assumption because trait or genetic similarity is not a true indicator of relatedness."
1. "Homoplasy (such as convergence or reversals)..." - This simple phrase alone motivated me to cite my source, because I used it almost as a direct quotation: "The various classes of homoplasy (convergence, parallelism, reversals) are not necessarily mutually exclusive and can be difficult to discriminate" (p. 1032).
2. "...often breaks with this assumption (of homology)..." - The author states that "Homoplasy is recognized by discordance with other characters in a phylogenetic analysis" (p. 1032). He invites the reader to see p. 1034, in which we get a quick glimpse of the process for detecting homoplasy: First, the relationships of taxa under study are selected; Secondly, traits of interest in the phylogram are mapped; Thirdly, the author determines whether each trait is present first and foremost in homology, if theres discordance in homology then convergence and parallelism are looked for, and lastly any possible reversals.
3. "...because trait or genetic similarity is not a true indicator of relatedness" - To understand this final point I'm making you really just have to read the whole article and understand the role of homoplasy in phylogenies. The issue can perhaps be put in condensed form in the following statement, "Although phylogenetic hypotheses are necessary, they are not always sufficient to resolve major questions involving parallelism and reversibility" (p. 1035).
Feel free to point out anything I've distorted.
