Quotes About Phenotype

Genes are the units of inheritance, the things that are selected by nature to be carried into the future. Nature sees the physical manifestation of a gene—the phenotype—and as a result of that trait enhancing survival, the DNA underwriting it succeeds, and is passed on down the generations. Genes are the templates on which our lives are built.

With only a little imagination we can see the gene as sitting at the centre of a radiating web of extended phenotypic power.

Putting these three things together we arrive at our own 'central theorem' of the extended phenotype: An animal's behaviour tends to maximize the survival of the genes 'for' that behaviour, whether or not those genes happen to be in the body of the particular animal performing it.

In the world of the extended phenotype, ask not how an animal's behaviour benefits its genes; ask instead whose genes it is benefiting.

Genes affect proteins, and proteins affect X which affects Y which affects Z which . . . affects the phenotypic character of interest.

The genes in one organism's cells, then, can have extended phenotypic influence on the living body of another organism; in this case a parasite's genes find phenotypic expression in the behaviour of its host.

We have now also seen that, in precisely the same sense as it is ever possible to talk of a gene 'for' a behaviour pattern, it is possible to talk of a gene, in one organism, 'for' a behaviour pattern (or other phenotypic characteristic) in another organism.

Just as every gene is the centre of a radiating field of influence on the world, so every phenotypic character is the centre of converging influences from many genes, both within and outside the body of the individual organism.

An extended phenotypic character is the product of the interaction of many genes whose influence impinges from both inside and outside the organism. The interaction is not necessarily harmonious—but then nor are gene interactions within bodies necessarily harmonious

From the viewpoint of this book an animal artefact, like any other phenotypic product whose variation is influenced by a gene, can be regarded as a phenotypic tool by which that gene could potentially lever itself into the next generation.

Phenotypic effects of genes, whether at the level of intracellular biochemistry, gross bodily morphology, or extended phenotype, are potentially devices by which genes lever themselves into the next generation, or barriers to their doing so. Incidental side-effects are not always effective as tools or barriers, and we do not bother to regard them as phenotypic expressions of genes, either at the conventional or the extended phenotype level.

Natural selection favours those genes that manipulate the world to ensure their own propagation. This leads to what I have called the central theorem of the extended phenotype: An animal's behaviour tends to maximize the survival of the genes 'for' that behaviour, whether or not those genes happen to be in the body of the particular animal performing it.

The gene's extended phenotypic effect, say an increase in the height of the dam, affects its chances of survival in precisely the same sense as in the case of a gene with a normal phenotypic effect, such as an increase in the length of the tail.

the conclusion I wish to draw is not really disputable. If host behaviour or physiology is a parasite adaptation, there must be (have been) parasite genes 'for' modifying the host, and the host modifications are therefore part of the phenotypic expression of those parasite genes. The extended phenotype reaches out of the body in whose cells the genes lie, reaches out to the living tissues of other organisms.

The second point of this present chapter is that the genes that bear upon any given extended phenotypic trait may be in conflict rather than in concert with one another.

If two beavers working on the same dam have different genes for dam height, the resulting extended phenotype will reflect the interaction between the genes, in the same way as bodies reflect gene interactions.

Finally, at the end of the chapter, we saw that genes 'sharing' a given extended phenotypic trait might come from different species, even different phyla and different kingdoms.

The other idea is that wherever there are 'shared' genetic influences on an extended phenotype, the shared influences may be in conflict with each other rather than cooperative

The phenotypic effects of a meme may be in the form of words, music, visual images, styles of clothes, facial or hand gestures, skills such as opening milk bottles in tits, or panning wheat in Japanese macaques.

The new copy of the meme is then in a position to broadcast its phenotypic effects, with the result that further copies of itself may be made in yet other brains.

Each gene works in a world of phenotypic consequences of other genes. Some of those other genes will be members of the same genome. Others will be members of the same gene-pool operating through other bodies. Yet others may be members of different gene-pools, different species, different phyla.

catching a glimpse of his rather hippyish form in a mirror, he wonders at this atavism of apparel, is it an inversion of foetal ontogeny, in which the phenotype passes through previous fashion stages? Soon there will be gaiters and gloves...I will probably die, he thinks, clad in animal skins.

By the 1970s and 1980s, the concept of 'phenotype'—which refers to surface features of humans such as skin colour, shape of nose, texture of hair, shape and size of skull, and so forth—on which those attempting to develop a tenable concept of race and a hierarchy of races had relied, had been compellingly refuted as a guide to genuine human variation.

And analogies were mostly meaningless—a matter of phenotype rather than genotype (to use another analogy).