On 2015 Mar 16, Donald Forsdyke commented:

INTRONS FIRST. The author points out that, for the human genome, Chargaff's second parity rule (PR2) remains significant for oligonucleotides extending to 9 nt and concludes that "the phenomenon must be non-random." Furthermore, he adds:

"At present, what is important is to unravel the origin of strand symmetry, which would contribute greatly to the study of the origin and evolution of genomes. First and foremost, it is necessary, also possible, to figure out whether the phenomenon is a result of convergence of genome evolution (Albrecht-Buehler, 2006; Fickett et al., 1992; Forsdyke and Bell, 2004; Lobry and Lobry, 1999) or, on the contrary, an original trait (vestige) of the primordial genome (Zhang and Huang, 2008, 2010; Zhang et al., 2013). If strand symmetry emerged by means of direct selection, the structural feature would be functional since its appearance. Otherwise, the structural feature would not necessarily be functional, or would be exploited to have a function, if any."

It is incorrect to list Forsdyke and Bell as supporters of the "convergence" hypothesis. As elaborated in 2013 Biological Theory 7: 196-203 ("Introns first"), Forsdyke holds PR2 to be an original trait related to the role of nucleic acid structure in the correction of errors by recombination. Thus, the trait has been functional since its appearance. Indeed, the primordial genome - one long "intron" - could not have existed without it. For more on this see Evolutionary Bioinformatics (2011, Springer, New York).

On 2015 Mar 16, Donald Forsdyke commented:

INTRONS FIRST. The author points out that, for the human genome, Chargaff's second parity rule (PR2) remains significant for oligonucleotides extending to 9 nt and concludes that "the phenomenon must be non-random." Furthermore, he adds:

"At present, what is important is to unravel the origin of strand symmetry, which would contribute greatly to the study of the origin and evolution of genomes. First and foremost, it is necessary, also possible, to figure out whether the phenomenon is a result of convergence of genome evolution (Albrecht-Buehler, 2006; Fickett et al., 1992; Forsdyke and Bell, 2004; Lobry and Lobry, 1999) or, on the contrary, an original trait (vestige) of the primordial genome (Zhang and Huang, 2008, 2010; Zhang et al., 2013). If strand symmetry emerged by means of direct selection, the structural feature would be functional since its appearance. Otherwise, the structural feature would not necessarily be functional, or would be exploited to have a function, if any."

It is incorrect to list Forsdyke and Bell as supporters of the "convergence" hypothesis. As elaborated in 2013 Biological Theory 7: 196-203 ("Introns first"), Forsdyke holds PR2 to be an original trait related to the role of nucleic acid structure in the correction of errors by recombination. Thus, the trait has been functional since its appearance. Indeed, the primordial genome - one long "intron" - could not have existed without it. For more on this see Evolutionary Bioinformatics (2011, Springer, New York).