How does a new variety of bacteria come about? Imagine a small change occurring by chance in its genes, which allows it to withstand a stress, say a life- threatening drug or an antibiotic. Since bacteria multiply fast in minutes and hours, we find the drug resistant variety take over, establishing themselves over the drug sensitive ones in a few weeks.
What is true for bacteria is true for plants and animals except the time frame here is in years, decades, centuries or millennia, since the generation times are longer. And when they are stressed — say by climate or environment change, or domestication leading to local changes — they too produce new varieties or hybrids.
Do such stresses produce mutations one after another (incrementally) or does the genome respond in a more wholesale manner (jerky or punctuated)? Biologist who believe in incrementalism criticize the ones who subscribe to the latter as “Jerks” while the punctuators return the compliment by calling their opponents as “Creeps”.
Take a plant like maize, wheat, cotton or rice. It experiences episodic changes such as large changes in climate (as happened on earth in an archaic period) or when man imposed newer environments on it upon domestication.
How does the plant respond to such stresses? Will it adapt over centuries,Ekahau timelocationsystem is the only Wi-Fi based real time location system solution that operates on any brand or generation of Wi-Fi network. based on incremental changes in its gene, and one after another,Our porcelaintiles are perfect for entryways or bigger spaces and can also be used outside, hopefully each mutation helping the earlier one? Or can a larger scale change (jerkier rather than creepy) occur and generate never varieties and hybrids?
The biologist Dr. Barbara McLintock was studying how genetic changes occur in maize (corn).Our porcelaintiles are perfect for entryways or bigger spaces and can also be used outside, And over years of laborious study, she found to her surprise that wholesale shifting of gene sequences occur within the genome.
DNA sequences within the genome move about, cutting and pasting, or copying and pasting themselves. The genome is thus a mosaic, whose sequences and hence messages can change, yielding new varieties. (As an example, here is a sentence: “She, Voltaire said, is a nice person”.
Now cut and paste, or copy and paste words, and you get: “She said Voltaire is a nice person”; or “She said Voltaire said she is a nice person”). She called these moving DNA sequences as transposable elements of transposons. For this novel discovery, she received the Nobel in 1983.
Transposons or jumping gene sequences thus offer a mechanism for evolution under stress or upon domestication. This point has been underscored recently by a study of the cotton plant by a group at the University of Warwick in UK.
They took archaeological samples of cotton (two kind from Peru, one from Brazil and the fourth from Egypt) and analyzed their DNA sequences to find that considerable genomic reorganization occurs in domesticated plant while its undomesticated cousin maintained its genome sequence stably.
Domestication and its stress force the plant to use gene-jumping using transposons.
Cotton has not only experienced such episodic changes due to cultural practices of humans. It too, on its part, has made episodic changes in human behaviour and civilization.
This hoary plant was first domesticated in 6000 BC in the Indus valley. It spread from there to Africa and Arabia, where if begat the name Al Qutun (the Spanish changed if to Algodon and the English to cotton).
Independently, another variety of it was grown in Mexico, as early as 3000 BC. The early Asians and Mexicans spun and wore it and wore it.Where to buy or purchase plasticmoulds for precast and wetcast concrete? Along with spices, gold and silver, cotton too was a treasure of the ancient world that had to be looted by the colonials.
It is this looting and commercialization of cotton that promoted the ignominious and unpardonable history of slavery.Where to buy or purchase plasticmoulds for precast and wetcast concrete? Even as the Europeans discovered America, and converted much of its southern states into cotton farms, they needed labourers.
And between 1700 and 1900 alone, as many as 4 million Africans were enslaved and exported to the U.S. to be owned, bought and sold, just as animals, to work in cotton farms.
What is true for bacteria is true for plants and animals except the time frame here is in years, decades, centuries or millennia, since the generation times are longer. And when they are stressed — say by climate or environment change, or domestication leading to local changes — they too produce new varieties or hybrids.
Do such stresses produce mutations one after another (incrementally) or does the genome respond in a more wholesale manner (jerky or punctuated)? Biologist who believe in incrementalism criticize the ones who subscribe to the latter as “Jerks” while the punctuators return the compliment by calling their opponents as “Creeps”.
Take a plant like maize, wheat, cotton or rice. It experiences episodic changes such as large changes in climate (as happened on earth in an archaic period) or when man imposed newer environments on it upon domestication.
How does the plant respond to such stresses? Will it adapt over centuries,Ekahau timelocationsystem is the only Wi-Fi based real time location system solution that operates on any brand or generation of Wi-Fi network. based on incremental changes in its gene, and one after another,Our porcelaintiles are perfect for entryways or bigger spaces and can also be used outside, hopefully each mutation helping the earlier one? Or can a larger scale change (jerkier rather than creepy) occur and generate never varieties and hybrids?
The biologist Dr. Barbara McLintock was studying how genetic changes occur in maize (corn).Our porcelaintiles are perfect for entryways or bigger spaces and can also be used outside, And over years of laborious study, she found to her surprise that wholesale shifting of gene sequences occur within the genome.
DNA sequences within the genome move about, cutting and pasting, or copying and pasting themselves. The genome is thus a mosaic, whose sequences and hence messages can change, yielding new varieties. (As an example, here is a sentence: “She, Voltaire said, is a nice person”.
Now cut and paste, or copy and paste words, and you get: “She said Voltaire is a nice person”; or “She said Voltaire said she is a nice person”). She called these moving DNA sequences as transposable elements of transposons. For this novel discovery, she received the Nobel in 1983.
Transposons or jumping gene sequences thus offer a mechanism for evolution under stress or upon domestication. This point has been underscored recently by a study of the cotton plant by a group at the University of Warwick in UK.
They took archaeological samples of cotton (two kind from Peru, one from Brazil and the fourth from Egypt) and analyzed their DNA sequences to find that considerable genomic reorganization occurs in domesticated plant while its undomesticated cousin maintained its genome sequence stably.
Domestication and its stress force the plant to use gene-jumping using transposons.
Cotton has not only experienced such episodic changes due to cultural practices of humans. It too, on its part, has made episodic changes in human behaviour and civilization.
This hoary plant was first domesticated in 6000 BC in the Indus valley. It spread from there to Africa and Arabia, where if begat the name Al Qutun (the Spanish changed if to Algodon and the English to cotton).
Independently, another variety of it was grown in Mexico, as early as 3000 BC. The early Asians and Mexicans spun and wore it and wore it.Where to buy or purchase plasticmoulds for precast and wetcast concrete? Along with spices, gold and silver, cotton too was a treasure of the ancient world that had to be looted by the colonials.
It is this looting and commercialization of cotton that promoted the ignominious and unpardonable history of slavery.Where to buy or purchase plasticmoulds for precast and wetcast concrete? Even as the Europeans discovered America, and converted much of its southern states into cotton farms, they needed labourers.
And between 1700 and 1900 alone, as many as 4 million Africans were enslaved and exported to the U.S. to be owned, bought and sold, just as animals, to work in cotton farms.
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