- Thread starter
- #101
Discovering something that has existed is not evolution.Good gawd, man.Name one beneficial mutation.Is that along the same, phony claim, “there are no beneficial mutations”?There’s no such thing as a ‘new gene’.No such thing as a beneficial mutation?
Good gawd, man.
Claim CB101:
Most mutations are harmful, so the overall effect of mutations is harmful.
Source:
Morris, Henry M. 1985. Scientific Creationism. Green Forest, AR: Master Books, pp. 55-57.
Watchtower Bible and Tract Society. 1985. Life--How Did It Get Here? Brooklyn, NY, pg. 100.
Response:
- Most mutations are neutral. Nachman and Crowell estimate around 3 deleterious mutations out of 175 per generation in humans (2000). Of those that have significant effect, most are harmful, but the fraction which are beneficial is higher than usually though. An experiment with E. coli found that about 1 in 150 newly arising mutations and 1 in 10 functional mutations are beneficial (Perfeito et al. 2007).
The harmful mutations do not survive long, and the beneficial mutations survive much longer, so when you consider only surviving mutations, most are beneficial.
- Beneficial mutations are commonly observed. They are common enough to be problems in the cases of antibiotic resistance in disease-causing organisms and pesticide resistance in agricultural pests (e.g., Newcomb et al. 1997; these are not merely selection of pre-existing variation.) They can be repeatedly observed in laboratory populations (Wichman et al. 1999). Other examples include the following:
- Mutations have given bacteria the ability to degrade nylon (Prijambada et al. 1995).
- Plant breeders have used mutation breeding to induce mutations and select the beneficial ones (FAO/IAEA 1977).
- Certain mutations in humans confer resistance to AIDS (Dean et al. 1996; Sullivan et al. 2001) or to heart disease (Long 1994; Weisgraber et al. 1983).
- A mutation in humans makes bones strong (Boyden et al. 2002).
- Transposons are common, especially in plants, and help to provide beneficial diversity (Moffat 2000).
- In vitro mutation and selection can be used to evolve substantially improved function of RNA molecules, such as a ribozyme (Wright and Joyce 1997).
- Whether a mutation is beneficial or not depends on environment. A mutation that helps the organism in one circumstance could harm it in another. When the environment changes, variations that once were counteradaptive suddenly become favored. Since environments are constantly changing, variation helps populations survive, even if some of those variations do not do as well as others. When beneficial mutations occur in a changed environment, they generally sweep through the population rapidly (Elena et al. 1996).
News Feature: Genetic mutations you want
To cure disease, researchers are starting to scour the genomes of the abnormally healthy. In 2009, researchers at the Broad Institute in Boston, led by geneticist David Altshuler, started recruiting elderly, overweight individuals who, by all accounts, ought to have type 2 diabetes but didn’t...www.pnas.org
Beneficial Mutation–Selection Balance and the Effect of Linkage on Positive Selection
When beneficial mutations are rare, they accumulate by a series of selective sweeps. But when they are common, many beneficial mutations will occur before any can fix, so there will be many different mutant lineages in the population concurrently. In ...www.ncbi.nlm.nih.gov
Something in a living creature having something become dominant is still working with the same pot.
One.
And not just a gene becoming dominant. A NEW gene.
More on the origination of new protein-coding genes
pandasthumb.org
Recently, we learned of an instance of the de novo origination of a new protein-coding gene in yeasts. This instance involved a mechanism or pathway that seems difficult to some, namely the random appearance of an open reading frame in an otherwise noncoding segment of DNA via judicious appearance of translation start and stop codons. The question naturally arises as to the relevance of such a pathway to real-life biology; was/is this a rather rare event that doesn’t really contribute to protein evolution, or is it a common means by which the protein-coding capacity of a genome is augmented?
