CLICK HERE TO READ THE REST OF THE ARTICLEGenetic Switch for Limbs and Digits Found in Primitive Fish: Before Animals First Walked On Land, Fish Carried Gene Program for Limbs
Genetic instructions for developing limbs and digits were present in primitive fish millions of years before their descendants first crawled on to land, researchers have discovered.
Genetic switches control the timing and location of gene activity. When a particular switch taken from fish DNA is placed into mouse embryos, the segment can activate genes in the developing limb region of embryos, University of Chicago researchers report in Proceedings of the National Academy of Sciences. The successful swap suggests that the recipe for limb development is conserved in species separated by 400 million years of evolution.
"The genetic switches that drive the expression of genes in the digits of mice are not only present in fish, but the fish sequence can actually activate the expression in mice," said Igor Schneider, PhD, postdoctoral researcher in the Department of Organismal Biology and Anatomy at the University of Chicago and lead author on the paper. "This tells us how the antecedents of the limb go back in time at every level, from fossils to genes."
Showing posts with label genetics. Show all posts
Showing posts with label genetics. Show all posts
Friday, July 29, 2011
Genetic Switch for Limbs and Digits Found in Primitive Fish
The fact that genetics time and again supports evolution at the molecular level amazes me. Not because the support is amazing, but because here is a field of science that came around more than 100 years after Darwin wrote his book, and it matches up! If evolution was somehow a fraud or in danger of being overturned, the level of fraud to have Darwin's book and ideas be supported at this level of science would be simply mind-boggling. He would have had to have had a time machine or something to pull it off. Either that, or he was simply correct, and the molecular genetics is yet one more prediction made by science that was in the end supported. Isn't it great when science actually works?
Thursday, January 06, 2011
Autism Treatment: Researchers Identify Possible Treatment for Impaired Sociability
Again, this looks at genetics as opposed to outside environmental factors. I think this is great news, not so much because it promises a cure or treatment, but rather that it looks to understand autism better. The treatment is a by-product. This is what basic research is good for. It gives you a foothold of understanding to complex and puzzling problems.
"Persons with Autism Spectrum Disorders are either disinterested in social interactions or find them unpleasant. They often don't understand what other people are thinking or feeling and misinterpret social cues," said Stephen I. Deutsch, MD, PhD, the Ann Robinson Chair and professor of psychiatry and behavioral sciences. "Sadly, persons with autism spectrum disorders are often painfully aware of their limited sociability, which can lead to profound feelings of sadness and frustration."
As part of their research, EVMS scientists verified that a specific mouse strain, known as the BALB/c mouse, is a valid animal model of the limited sociability seen in persons with ASD. In the presence of another mouse, BALB/c mice move as far away as possible and do not interact as normal mice do -- just like people with autism often avoid making social contact with other people.
This finding gave researchers a way to test whether an existing medication can alter the function of certain receptors in the brain known to affect sociability and help the animals be more at ease around others. The medication used, D-Cycloserine, originally was developed to treat tuberculosis, but previous studies showed, by chance, that it might change social behavior. In preliminary studies at EVMS, the medication appeared to resolve the Balb/c mouse's deficits of sociability; it behaved as a normal mouse would when placed near another.
Dr. Deutsch will discuss the research at EVMS' Quarterly Autism Education Series at noon, Dec. 14, in the school's Hofheimer Hall auditorium.
EVMS' laboratory studies with the Balb/c mouse led its investigators to hypothesize that D-Cycloserine could ease the impaired sociability of persons with autism, such as avoiding eye contact and personal interaction. Those traits can severely limit the possibility of employment and independent living for someone with autism.
"What makes this important is you might have someone with a 125 or 130 IQ who's unemployable" because of their social impairments, said Maria R. Urbano, MD, associate professor of psychiatry and behavioral sciences.
Dr. Urbano is moving this promising research from the laboratory directly to patient care by starting a pilot clinical trial of D-Cycloserine in adolescent and young adult patients with autism spectrum disorders. The trial will show whether the medication, which is already known to be safe for use in humans, has similar effects on the sociability deficits of persons with autism as it did in the mice. Her research is supported by a grant from the Hampton Roads Community Foundation.
Autism Treatment: Researchers Identify Possible Treatment for Impaired Sociability
ScienceDaily (Dec. 8, 2010) — Eastern Virginia Medical School researchers have identified a potential novel treatment strategy for the social impairment of people with Autism Spectrum Disorders (ASD), an aspect of the condition that has a profound impact on quality of life.
"Persons with Autism Spectrum Disorders are either disinterested in social interactions or find them unpleasant. They often don't understand what other people are thinking or feeling and misinterpret social cues," said Stephen I. Deutsch, MD, PhD, the Ann Robinson Chair and professor of psychiatry and behavioral sciences. "Sadly, persons with autism spectrum disorders are often painfully aware of their limited sociability, which can lead to profound feelings of sadness and frustration."
As part of their research, EVMS scientists verified that a specific mouse strain, known as the BALB/c mouse, is a valid animal model of the limited sociability seen in persons with ASD. In the presence of another mouse, BALB/c mice move as far away as possible and do not interact as normal mice do -- just like people with autism often avoid making social contact with other people.
This finding gave researchers a way to test whether an existing medication can alter the function of certain receptors in the brain known to affect sociability and help the animals be more at ease around others. The medication used, D-Cycloserine, originally was developed to treat tuberculosis, but previous studies showed, by chance, that it might change social behavior. In preliminary studies at EVMS, the medication appeared to resolve the Balb/c mouse's deficits of sociability; it behaved as a normal mouse would when placed near another.
Dr. Deutsch will discuss the research at EVMS' Quarterly Autism Education Series at noon, Dec. 14, in the school's Hofheimer Hall auditorium.
EVMS' laboratory studies with the Balb/c mouse led its investigators to hypothesize that D-Cycloserine could ease the impaired sociability of persons with autism, such as avoiding eye contact and personal interaction. Those traits can severely limit the possibility of employment and independent living for someone with autism.
"What makes this important is you might have someone with a 125 or 130 IQ who's unemployable" because of their social impairments, said Maria R. Urbano, MD, associate professor of psychiatry and behavioral sciences.
Dr. Urbano is moving this promising research from the laboratory directly to patient care by starting a pilot clinical trial of D-Cycloserine in adolescent and young adult patients with autism spectrum disorders. The trial will show whether the medication, which is already known to be safe for use in humans, has similar effects on the sociability deficits of persons with autism as it did in the mice. Her research is supported by a grant from the Hampton Roads Community Foundation.
Monday, January 03, 2011
Three Billion-Year-Old Genomic Fossils Deciphered
There are still people who deny evolution. This mystifies me. Again, if evolution was not true, then the fact that a 19th century Victorian Englishman came up with it, and somehow managed to have pretty much every discovery in biology, medicine, zoology, etc. support him borders on the ridiculous. So I read with interest this article:
Because all living organisms inherit their genomes from ancestral genomes, computational biologists at MIT reasoned that they could use modern-day genomes to reconstruct the evolution of ancient microbes. They combined information from the ever-growing genome library with their own mathematical model that takes into account the ways that genes evolve: new gene families can be born and inherited; genes can be swapped or horizontally transferred between organisms; genes can be duplicated in the same genome; and genes can be lost.
The scientists traced thousands of genes from 100 modern genomes back to those genes' first appearance on Earth to create a genomic fossil telling not only when genes came into being but also which ancient microbes possessed those genes. The work suggests that the collective genome of all life underwent an expansion between 3.3 and 2.8 billion years ago, during which time 27 percent of all presently existing gene families came into being.
Eric Alm, a professor in the Department of Civil and Environmental Engineering and the Department of Biological Engineering, and Lawrence David, who recently received his Ph.D. from MIT and is now a Junior Fellow in the Harvard Society of Fellows, have named this period the Archean Expansion.
Because so many of the new genes they identified are related to oxygen, Alm and David first thought that the emergence of oxygen might be responsible for the Archean Expansion. Oxygen did not exist in the Earth's atmosphere until about 2.5 billion years ago when it began to accumulate, likely killing off vast numbers of anerobic life forms in the Great Oxidation Event.
"The Great Oxidation Event was probably the most catastrophic event in the history of cellular life, but we don't have any biological record of it," says Alm.
Closer inspection, however, showed that oxygen-utilizing genes didn't appear until the tail end of the Archean Expansion 2.8 billion years ago, which is more consistent with the date geochemists assign to the Great Oxidation Event.
Instead, Alm and David believe they've detected the birth of modern electron transport, the biochemical process responsible for shuttling electrons within cellular membranes. Electron transport is used to breathe oxygen and by plants and some microbes during photosynthesis when they harvest energy directly from the sun. A form of photosynthesis called oxygenic photosynthesis is believed to be responsible for generating the oxygen associated with the Great Oxidation Event, and is responsible for the oxygen we breathe today.
The evolution of electron transport during the Archean Expansion would have enabled several key stages in the history of life, including photosynthesis and respiration, both of which could lead to much larger amounts of energy being harvested and stored in the biosphere.
"Our results can't say if the development of electron transport directly caused the Archean Expansion," says David. "Nonetheless, we can speculate that having access to a much larger energy budget enabled the biosphere to host larger and more complex microbial ecosystems."
David and Alm also went on to investigate how microbial genomes evolved after the Archean Expansion by looking at the metals and molecules associated with the genes and how those changed in abundance over time. They found an increasing percentage of genes using oxygen, and enzymes associated with copper and molybdenum, which is consistent with the geological record of evolution.
"What is really remarkable about these findings is that they prove that the histories of very ancient events are recorded in the shared DNA of living organisms," says Alm. "And now that we are beginning to understand how to decode that history, I have hope that we can reconstruct some of the earliest events in the evolution of life in great detail."
Three Billion-Year-Old Genomic Fossils Deciphered
ScienceDaily — About 580 million years ago, life on Earth began a rapid period of change called the Cambrian Explosion, a period defined by the birth of new life forms over many millions of years that ultimately helped bring about the modern diversity of animals. Fossils help palaeontologists chronicle the evolution of life since then, but drawing a picture of life during the 3 billion years that preceded the Cambrian Period is challenging, because the soft-bodied Precambrian cells rarely left fossil imprints. However, those early life forms did leave behind one abundant microscopic fossil: DNA.
Because all living organisms inherit their genomes from ancestral genomes, computational biologists at MIT reasoned that they could use modern-day genomes to reconstruct the evolution of ancient microbes. They combined information from the ever-growing genome library with their own mathematical model that takes into account the ways that genes evolve: new gene families can be born and inherited; genes can be swapped or horizontally transferred between organisms; genes can be duplicated in the same genome; and genes can be lost.
The scientists traced thousands of genes from 100 modern genomes back to those genes' first appearance on Earth to create a genomic fossil telling not only when genes came into being but also which ancient microbes possessed those genes. The work suggests that the collective genome of all life underwent an expansion between 3.3 and 2.8 billion years ago, during which time 27 percent of all presently existing gene families came into being.
Eric Alm, a professor in the Department of Civil and Environmental Engineering and the Department of Biological Engineering, and Lawrence David, who recently received his Ph.D. from MIT and is now a Junior Fellow in the Harvard Society of Fellows, have named this period the Archean Expansion.
Because so many of the new genes they identified are related to oxygen, Alm and David first thought that the emergence of oxygen might be responsible for the Archean Expansion. Oxygen did not exist in the Earth's atmosphere until about 2.5 billion years ago when it began to accumulate, likely killing off vast numbers of anerobic life forms in the Great Oxidation Event.
"The Great Oxidation Event was probably the most catastrophic event in the history of cellular life, but we don't have any biological record of it," says Alm.
Closer inspection, however, showed that oxygen-utilizing genes didn't appear until the tail end of the Archean Expansion 2.8 billion years ago, which is more consistent with the date geochemists assign to the Great Oxidation Event.
Instead, Alm and David believe they've detected the birth of modern electron transport, the biochemical process responsible for shuttling electrons within cellular membranes. Electron transport is used to breathe oxygen and by plants and some microbes during photosynthesis when they harvest energy directly from the sun. A form of photosynthesis called oxygenic photosynthesis is believed to be responsible for generating the oxygen associated with the Great Oxidation Event, and is responsible for the oxygen we breathe today.
The evolution of electron transport during the Archean Expansion would have enabled several key stages in the history of life, including photosynthesis and respiration, both of which could lead to much larger amounts of energy being harvested and stored in the biosphere.
"Our results can't say if the development of electron transport directly caused the Archean Expansion," says David. "Nonetheless, we can speculate that having access to a much larger energy budget enabled the biosphere to host larger and more complex microbial ecosystems."
David and Alm also went on to investigate how microbial genomes evolved after the Archean Expansion by looking at the metals and molecules associated with the genes and how those changed in abundance over time. They found an increasing percentage of genes using oxygen, and enzymes associated with copper and molybdenum, which is consistent with the geological record of evolution.
"What is really remarkable about these findings is that they prove that the histories of very ancient events are recorded in the shared DNA of living organisms," says Alm. "And now that we are beginning to understand how to decode that history, I have hope that we can reconstruct some of the earliest events in the evolution of life in great detail."
The figure shows the evolution of gene families in ancient genomes across the Tree of Life. The sizes of the little pie charts scale with the number of evolutionary events in lineages, slices indicate event types: gene birth (red), duplication (blue), horizontal gene transfer (green), and loss (yellow). The Archean Expansion period (3.33 to 2.85 billion years ago) is highlighted in green. (Credit: Lawrence David)
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