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-------------------------------- 2288 - The Diversity of Life
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- Scientists are now working on all the small stuff that they have not counted yet. There re many more species to be counted that are insects and microbes. A Microbe is any organism too small to see with the naked eye. The average teaspoon of water, soil, or ice contains millions of micro-organisms that have never been counted or catalogued.
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- Technology has brought science new techniques to collect the DNA of these small organisms. It is called metagenomics, the study of genomes recovered from the environment rather than from clonal cultures.
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- In biology the genome of an organism is its whole hereditary information encoded in its DNA, deoxyribonucleic acid, that resides in every cell to give the genetic instructions for development of proteins.
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- The technique involves taking a sample from the environment, pooling the DNA from all the different species present, fracturing it into a mixture of short fragments, and then sequencing the lot. From that sequencing scientists work backwards putting the fragments back together like a molecular jigsaw puzzle to reconstruct the individual genes and hopefully the entire genome.
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- UC Berkeley is using metagenomics on a toxic mine in northern California where only a small range of microbe species can survive.
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- The water running out of the mine is more acidic than battery acid. The concentration of metals is so high drinking the water would be lethal. The temperature in the mine is 104 F.
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- This resulted in the discovery of a new phylum of archaea. Archaea is one of the three main branches of the tree-of -life along with eukaryotes (animals and plants) and bacteria. The new archaea are only 200 nanometers across. The wavelengths of blue light is 400 nanometers so you could not see these microbes with an optical microscope. They are 1/5 the size of bacteria. That is the smallest living organism found to date.
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- Archaea are one cell organisms that look like bacteria but are genetically different. To classify organisms you start with the five kingdoms: animals, plants, fungus, monerans (bacteria), and protests (slime mold).
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- Then under each kingdom is a classification of phylum’s, example is all vertebrates. Under each phylum category is a Class, examples are mammals. Under each Class is an Order, example is the Order of Primates. Under Order you have the Family, example 2-legged. Under Family is the Genus, example homo, meaning humans. Then under Genus you have Species, such as sapiens, meaning modern humans.
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- The Earth has been home to millions of individual species that have come and gone. 99% of all species that have existed are now extinct. Today we have identified 1% of those left. 99% is yet to be found and classified. The archaea found in the mine generate energy for CO2 and N2 fixation and metabolic activity via oxidation of ferrous iron. The ferric iron byproduct promotes dissolution of metal sulfide minerals.
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- Other microbes coexisting with the Fe-oxidizers generate energy by oxidation of sulfur compounds formed during oxidative dissolution of sulfide minerals. Together, these processes lead to acidification of the environment. That is why the water is acidic! The microbes have formed a community living off each other.
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- Scientists collecting samples of seawater off Bermuda found 1,200,000 new genes from thousands of different microscopic species. Water samples collected from the east coast of US to the Caribbean, the Panama Canal Galapagos, to French Polynesia, sampling seawater every few hundred kilometers. The collection yielded 6,000,000 new genes.
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- Seawater collected from 68 ocean sites found viruses that are completely different from their land-based counterparts.
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- Megagenomics may very well lead us to new ways to discover pollution. Like canaries in the coal mines. Microbes could foretell of toxic pollution that could soon destroy a coral reef for example. This could give humans time to reverse the trends before it is too late.
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- Today the oceans are becoming more acidic due to the increased CO2 pollution caused by humans burning fossil fuels. Scientists are using metagenomics to learn the effects this has on the ocean’s microbe communities.
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- Discovering new genes means discovering new proteins, which means potential to design new drugs to cure disease.
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- Lawrence Berkeley Labs has sequenced genetic material from a 38,000 year old Neanderthal thigh bone. Using metagenomics techniques they searched through 6,000,000 base pairs to pick out 65,000 base pairs of Neanderthal DNA, .002% of the entire genome. Their conclusion is that today’s humans share 99.5% the same DNA. And, 700,000 years ago they shared a common ancestor.
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- A similar approach was done on the Wooly Mammoth DNA recovered in the permafrost in Siberia. You will be happy to learn that we humans do not share common DNA with Wooly Mammoths going back at least 3,000,000 years.
- Not too long ago some famous scientists said that science was coming to an end. We have learned all the basic laws of physics and biology and it was just a matter of adding more accuracy beyond the decimal points.
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- Well, in recent years astronomers have embarrassingly determined that they know only 5% of the Universe, the 95% is Dark Matter and Dark Energy that they do not understand. Biologists have catalogued 1,800,000 species but they have done only 1% of the job to be done. There is so much to the tree-of-life that we do not understand.
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- We had better not listen to these “famous scientists” and keep our kids in school. It appears that they still have a lot more to learn.
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- March 1, 2019 741 742
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-------------------------- Saturday, March 2, 2019 --------------------------
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