Group items tagged

Recent advances in forensic DNA testing are now paving the way for reforming the manner by which cases are resolved in courts of law through the way suspected offenders are apprehended during a criminal investigation. Firstly, the availability of new markers which are more variable across different populations, adds to the increased power of discrimination once more genetic markers are used. From the time when DNA testing only involved seven to nine genetic markers to evaluate if crime scene evidence matches a suspect’s profile, as well as to determine relationships, to the current battery of 21 autosomal markers and 23 male-specific markers, the capacity of DNA profiling to differentiate individuals has increased significantly. The use of automated and expert systems for large-scale analysis has also been found to reduce manual errors and to increase output per unit time. The use of several dyes in a single multiplex system provides more information from the same amount of genetic material compared to reactions targeting only one genetic marker but requiring the same amount of DNA that was common in the early 1990s.

The first technique of genetic engineering, the plasmid method, is the most familiar technique of the three, and is generally used for altering microorganisms such as bacteria. In the plasmid method, a small ring of DNA called a plasmid (generally found in bacteria) is placed in a container with special restriction enzymes that cut the DNA at a certain recognizable sequence. The same enzyme is then used to treat the DNA sequence to be engineered into the bacteria; this procedure creates "sticky ends" that will fuse together if given the opportunity. Next, the two separate cut-up DNA sequences are introduced into the same container, where the sticky ends allow them to fuse, thus forming a ring of DNA with additional content. new enzymes are added to help cement the new linkages, and the culture is then separated by molecular weight. Those molecules that weigh the most have successfully incorporated the new DNA, and they are to be preserved. The next step involves adding the newly formed plasmids to a culture of live bacteria with known genomes, some of which will take up the free-floating plasmids and begin to express them. In general, the DNA introduced into the plasmid will include not only instructions for making a protein, but also antibiotic-resistance genes. These resistance genes can then be used to separate the bacteria which have taken up the plasmid from those that have not. The scientist simply adds the appropriate antibiotic, and the survivors are virtually guaranteed (barring spontaneous mutations) to possess the new genes.

Next, the scientist allows the successfully altered bacteria to grow and reproduce. They can now be used in experiments or put to work in industry. Furthermore, the bacteria can be allowed to evolve on their own, with a "selection pressure" provided by the scientist for producing more protein. Because of the power of natural selection, the bacteria produced after many generations will outperform the best of the early generations. Many people strongly object to the plasmid method of genetic engineering because they fear that the engineered plasmids will be transferred into other bacteria which would cause problems if they expressed the gene. Lateral gene transfer of this type is indeed quite common in bacteria, but in general the bacteria engineered by this method do not come in contact with natural bacteria except in controlled laboratory conditions. Those bacteria that will be used in the wild - for example, those that could clean up oil spills - are generally released for a specific purpose and in a specific area, and they are carefully supervised by scientists.

Professor Julian Savulescu said that creating so-called designer babies could be considered a "moral obligation" as it makes them grow up into "ethically better children". The expert in practical ethics said that we should actively give parents the choice to screen out personality flaws in their children as it meant they were then less likely to "harm themselves and others". The academic, who is also editor-in-chief of the Journal of Medical Ethics, made his comments in an article in the latest edition of Reader's Digest. He explained that we are now in the middle of a genetic revolution and that although screening, for all but a few conditions, remained illegal it should be welcomed.

Cloning animal models of disease Much of what researchers learn about human disease comes from studying animal models such as mice. Often, animal models are genetically engineered to carry disease-causing mutations in their genes.

To clone or not to clone: that is the question. The prospect of cloning humans is highly controversial and raises a number of ethical, legal and social challenges that need to be considered.

Brazil Plans to Clone Its Endangered Species

The scientists have already spent the past two years collecting 420 genetic samples for the species—mostly from dead specimens found in the Cerrado savanna region—and are now waiting for legal authorization to start the cloning.

If they receive government approval, the species they’ll be working with would include the maned wolf (Chrysocyon brachyurus); jaguar (Panthera onca); black lion tamarin (Leontopithecus chrysopygus); bush dog (Speothos venaticus); Brazilian aardvark, also known locally as coati (Nasua nasua); collared anteater (Tamandua tetradactyla); gray brocket deer (Mazama gouazoubira); and bison (Bison bison).

What is a Clone

In biology, a clone is a cell or an organism that is genetically identical to another cell or organism.

How was Dolly Created? Dolly is different. She was generated from a specialized adult cell, not from an unspecialized embryonic cell.

The classical twin study design relies on studying twins raised in the same family environments. Monozygotic (identical) twins share all of their genes, while dizygotic (fraternal) twins share only about 50 percent of them. So, if a researcher compares the similarity between sets of identical twins to the similarity between sets of fraternal twins for a particular trait, then any excess likeness between the identical twins should be due to genes rather than environment.Researchers use this method, and variations on it, to estimate the heritability of traits: The percentage of variance in a population due to genes. Modern twin studies also try to quantify the effect of a person's shared environment (family) and unique environment (the individual events that shape a life) on a trait.The assumptions those studies rest on--questioned by some psychologists, including, in recent work, Jaccard--include: