Mutations Quotes

“The researchers looked deeper into these observations, in hopes of gaining insight into the mechanisms underlying the high evolutionary rate and extraordinary immunologic plasticity of influenza HA. They probed in more detail the precise codons that are used by the virus to encode the influenza HA1 protein. The discriminated between codons on the basis of volatility. Each three-nucleotide codon is related by a single nucleotide change to nine 'mutational neighbours.' Of those nine mutations, some proportion change the codon to a synonymous codon and some change it to a nonsynonymous one, which directs the incorporation of a different amino acid into the protein. More volatile codons are those for which a larger proportion of those nine mutational neighbours encode an amino acid change. The use of particular codons in a gene at a frequency that is disproportionate to their random selection for encoding a chosen amino acid is termed codon bias. Such bias is common and is influenced by many factors, but here the collaborators found strong evidence for codon bias that was particular for and restricted to the amino acids making up the HA1 epitopes. Remarkably, they observed that influenza employs a disproportionate number of volatile codons in its epitope-coding sequences. There was a bias for the use of codons that had the fewest synonymous mutational neighbours. In other words, influenza HA1 appears to have optimized the speed with which it can change amino acids in its epitopes. Amino acid changes can arise from fewer mutational events. The antibody combining regions are optimized to use codons that have a greater likelihood to undergo nonsynonymous single nucleotide substitutions : they are optimized for rapid evolution.”

“Somewhere in our DNA must lie the key mutation (or, more probably, mutations) that set us apart—the mutations that make us the sort of creature that could wipe out its nearest relative, then dig up its bones and reassemble its genome.”

“Natural selection eliminates and maybe maintains, but it doesn't create... Neo-Darwinists say that new species emerge when mutations occur and modify an organism. I was taught over and over again that the accumulation of random mutations led to evolutionary change [which] led to new species. I believed it until I looked for evidence.”

“In the abstract, it might be tempting to imagine that irreducible complexity simply requires multiple simultaneous mutations - that evolution might be far chancier than we thought, but still possible. Such an appeal to brute luck can never be refuted... Luck is metaphysical speculation; scientific explanations invoke causes.”

“We are only chance visitants to this jungle of blind mutations. The natural world existed when we did not, and it will continue to exist long after we are gone. The supernatural crept into life only when the door of consciousness was opened in our heads. The moment we stepped through that door, we walked out on nature. Say what we will about it and deny it till we die--we are blighted by our knowing what is too much to know and too secret to tell one another if we are to stride along our streets, work at our jobs, and sleep in our beds. It is the knowledge of a race of beings that is only passing through this shoddy cosmos.”

“New mutations don't create new species”

“Freedom comes only to those who no longer ask of life that it shall yield them any of those personal goods that are subject to the mutations of time.”

“Murphy's face went through several mutations as he spoke, as if small animals were scurrying about just beneath his skin.”

“I was taught over and over again that the accumulation of random mutations led to evolutionary change - led to new species. I believed it until I looked for evidence.”