Visk (evolution)

Re: Visk (evolution)


You are NOT serious, are you?

Name ANY mutation which is beneficial?

Re: Visk (evolution)


To begin with all the mutations the created you (as a species).

The majority of mutations are benign and have no immediate affect what so ever. A small number are fatal. What mutations do is elevate the level of genetic variation in a species which makes some members more capably of profiting from any change in the environment of that species. The key to evolution (change) is variation in the genotype.

Re: Visk (evolution)


Don't generalise...name a specific mutation?

Beneficial mutations:
-decay-resistant teeth, which my husband and son have but my daughter and I do not (not a problem before sugary diets)
-resistance to new viruses and strains of bacteria
-alcohol metabolization (deficient in some native Americans)
-ability to remember and recall trivia
-ability to conceptualize the unknown, from quarks to quasars
-ability to think logically and distinguish scientific truth from uninformed opinion

Re: Visk (evolution)


An enlarged lateral proximal condyle (the upper end of the tibiae or the lower half of your knee) It locks the knee and allows for an upright posture and bipedalism. It appeared about 4.5 mya. and the first primate to udoubtedly be bipedal was Australopithecus amamensis.

You have stated present observable realities, but how are they mutations?
And from what did they mutate?

Most mutations are neutral. Nachman and Crowell estimate around 3 deleterious mutations out of 175 per generation in humans [Nachman and Crowell 2000]. Of those that have significant effect, most are harmful, but a significant fraction are beneficial. The harmful mutations don't 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]. (No, these are not merely selection of pre-existing variation.) They can be repeatedly observed in laboratory populations [Wichman et al. 1999]. Other examples include:
• 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]
• . . . or to heart disease [Weisgraber et al. 1983; Long 1994].
• A mutation in humans makes bones strong [Boyden et al. 2002].
• Transposes are common, especially in plants, and help to provide beneficial diversity [Moffat 2000].
• Mutation and selection in vitro 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 which helps the organism in one circumstance could harm it in another. When the environment changes, variations which once were counter adaptive suddenly become favored. Since environments are constantly changing, variation helps populations survive, even if some of those variations don't do as well as others. When beneficial mutations occur in a changed environment, they generally sweep through the population rapidly [Elena et al. 1996].


High mutation rates are advantageous in some environments. Hypermutable strains of Pseudomonas aeruginosa were found more commonly in the lungs of cystic fibrosis patients, where antibiotics and other stresses increase selection pressure and variability [Oliver et al. 2000].


References:

1. Boyden, Ann M., Junhao Mao, Joseph Belsky, Lyle Mitzner, Anita Farhi, Mary A. Mitnick, Dianqing Wu, Karl Insogna, and Richard P. Lifton, 2002. High bone density due to a mutation in LDL-receptor-related protein 5. New England Journal of Medicine 346: 1513-1521, May 16, 2002.
2. Dean, M. et al., 1996. Genetic restriction of HIV-1 infection and progression to AIDS by a deletion allele of the CKR5 structural gene. Science 273: 1856-1862.
3. Elena, S. F., V. S. Cooper and R. E. Lenski, 1996. Punctuated evolution caused by selection of rare beneficial mutations. Science 272: 1802-1804.
4. FAO/IAEA, 1977. Manual on Mutation Breeding, 2nd ed. Vienna: International Atomic Energy Agency.
5. Long, Patricia, 1994. A town with a golden gene. Health 8(1) (Jan/Feb.): 60-66.
6. Moffat, Anne S., 2000. Transposons help sculpt a dynamic genome. Science 289: 1455-1457.
7. Morris, Henry M., 1974. Scientific Creationism, Green Forest, AR: Master Books.
8. Nachman, M. W. and S. L. Crowell, 2000. Estimate of the mutation rate per nucleotide in humans. Genetics 156(1): 297-304.
9. Newcomb, R. D. et al., 1997. A single amino acid substitution converts a carboxylesterase to an organophosporus hydrolase and confers insecticide resistance on a blowfly. Proceedings of the National Academy of Science USA 94: 7464-7468.
10. Oliver, Antonio et al., 2000. High frequency of hypermutable Pseudomonas aeruginosa in cystic fibrosis lung infection. Science 288: 1251-1253. See also: Rainey, P. B. and R. Moxon, 2000. When being hyper keeps you fit. Science 288: 1186-1187. See also: LeClerc, J. E. and T. A. Cebula, 2000. Pseudomonas survival strategies in cystic fibrosis (letter), 2000. Science 289: 391-392.
11. Prijambada, I. D., S. Negoro, T. Yomo and I. Urabe, 1995. Emergence of nylon oligomer degradation enzymes in Pseudomonas aeruginosa PAO through experimental evolution. Applied and Environmental Microbiology 61(5): 2020-2022.
12. Weisgraber K. H., S. C. Rall Jr., T. P. Bersot, R. W. Mahley, G. Franceschini, and C. R. Sirtori, 1983. Apolipoprotein A-I Milano. Detection of normal A-I in affected subjects and evidence for a cysteine for arginine substitution in the variant A-I. Journal of Biological Chemistry 258: 2508-2513.
13. Wichman, H. A. et al., 1999. Different trajectories of parallel evolution during viral adaptation. Science 285: 422-424.
14. Wright, M. C. and G. F. Joyce, 1997. Continuous in vitro evolution of catalytic function. Science 276: 614-617. See also: Ellington, A. D., M. P. Robertson and J. Bull, 1997. Ribozymes in wonderland. Science 276: 546-547.

good post tryagain

Drug resistance in numerous bacteria.

Increased melenin in the skin of Peoples who are near the equator (for protection from the sun), versus fair skin in Peoples from northern or souther latitudes.

A mutation among leopards make their spots cover their entire coat. This has proven to be beneficial in the Africas high cold mountains where these "black panthers" have become plentiful.

Mosquito resistance to pesticide, twarted WHO eradicationcampaign aimed at the mosquito responsible for transmitting malaria.

Cattle with increased milk production increases their chances of passing on their genes given the nature of their symbiotic relationship with humans.

White skin among humans, alows more vitamin d to be produced with the same amount of sunlight, but reduces resistance to sunlight. Beneficial in the far northern and southern hemisphere. (oops, already taken)

Thank you Acquiunk, "at the place below (agwi)" the falls. "A hill thirty or forty rods s.e. from" the upper falls of the Quinebaug River, at Danielsonville; "which said falls are known to the Indians by the name of Ac-qui-unk." Chandler, 1705; CT Archives, T. & L., ii. 187; Larned's History of Windham County, 115. According to testimony by Passagcogon, a Quinebaug Indian, in 1704: A small fort stood on the hill in which only four families had wigwams. How! :wink:

Thankyou tryagain. I am not native American but an archaeologist. I was born and raised not far from that spot.

So, the point of this thread is that mutations occur? who has denied thaT? However , mutations must first be effective, they must be at the proper coding locus, and they must be able to turn off oron, for a particular trait.
This complicates the phenotypic response just as recobination, or any other means that is more dependent upon genic variability.

often mutations act in concert with another coding triplet (codon) to affect the "switching" function. Thats why the increased melanin and malaria protection and sickling usually come together as a package deal.

also the variability conferred on plants is really not a mutation but a mere transposition and "folding" of a section of plant genome. Margulis had found that such traansposition is quite common in providing great fields of variability in plant species. Since this occurs quite frequently, transpositions dont confer any fitness until a special environmental condition impresses fitness by "dumb luck"

Acquiunk writes, "I was born and raised not far from that spot."

Ac - Dc - Bc - Ad. Are you sure, you are an Archaeologist, with a compass?

X MARKS THE "DAMN'D SPOT"
"Out, damn'd spot!" Lady Macbeth cries, "out, I say!" (V:i:35). The specific spots in the setting of Macbeth are Scotland and England. :wink:

Archaeologist's rule; or at least record extremely accurately. Happy Thanksgiving.