ronse@prlb2.UUCP (Christian Ronse) (10/13/87)
divergence of function? I have read that the paleontologist W.K. Gregory proposed in 1935 (Quart. Rev. Biol. 10) that a frequent occurrence in evolution is the sudden replication of an existing body part followed by a subsequent elaboration and divergence of function of the two parts. Is this suggestion verified? I am particularly interested in the case of the evolution of the human (or simply primate) brain. Such a mechanism has been invoked to explain the multiplicity of visual areas in the primate occipital lobe (Allman, 1977), and the similarity between the perception of short-range movement and stereopsis (Anstis, 1970). Any pointer to serious articles or books appreciated. Christian Ronse maldoror@prlb2.UUCP {uunet|philabs|mcvax|...}!prlb2!{maldoror|ronse} ``Innamorata, mio cuore tremente, Voglio morire.'' Jules Verne
pell@boulder.Colorado.EDU (Anthony Pelletier) (10/14/87)
In article <369@prlb2.UUCP> ronse@prlb2.UUCP (Christian Ronse) writes: >divergence of function? > >I have read that the paleontologist W.K. Gregory proposed in 1935 (Quart. Rev. >Biol. 10) that a frequent occurrence in evolution is the sudden replication of >an existing body part followed by a subsequent elaboration and divergence of >function of the two parts. Is this suggestion verified? I can't speak to the evolution of organs, but the model does seem to fit the evolution of genes. There are, in eukariotes mostly, gene families. Different genes at different loci on the chromosomes that perform different, but very similar functions. If one looks at the DNA sequence of these genes, one finds them to be very closely related. Examples of these families include the Tubulin and the Hemoglobin families (|one might even include myoglobin in the later). There are also "pseudo-genes" which are non-funtional copies of know genes, often lacking introns and upstream control regions. These pseudo-genes also are often divergent from the parent copy at the DNA sequence level. These observations as wellas others have led people to suggest that new genes evolve from old ones by duplication and divergence. I have a bit of trouble with, say, a prehensile thumb arising first through a duplication of existing thumbs...but, in other cases, it might work. > >I am particularly interested in the case of the evolution of the human (or >simply primate) brain. > >Christian Ronse Sorry, brain function and evolution is something I try to avoid (+: I don't know a thing abut it. tony molecular etc. bio. boulder, co 80303-0347