Due to the success of large-scale biology projects such as the sequencing of the human genome, the suffix "-ome" is now being used in other research contexts.
Proteomics is an example. The DNA sequence of genes carries the instructions, or code, for building proteins. Proteomics, therefore, is a similar large-scale analysis of all the proteins in an organism, tissue type, or cell called the proteome. Proteomics can be used to reveal specific, abnormal proteins that lead to diseases, such as certain forms of cancer. The terms "pharmacogenetics" and "pharmacogenomics" are often used interchangeably in describing the intersection of pharmacology the study of drugs, or pharmaceuticals and genetic variability in determining an individual's response to particular drugs.
The terms may be distinguished in the following way. Pharmacogenetics is the field of study dealing with the variability of responses to medications due to variation in single genes. Pharmacogenetics takes into account a person's genetic information regarding specific drug receptors and how drugs are transported and metabolized by the body. The goal of pharmacogenetics is to create an individualized drug therapy that allows for the best choice and dose of drugs.
One example is the breast cancer drug trastuzumab Herceptin. This therapy works only for women whose tumors have a particular genetic profile that leads to overproduction of a protein called HER2. See: Genetics, Disease Prevention and Treatment. Pharmacogenomics is similar to pharmacogenetics, except that it typically involves the search for variations in multiple genes that are associated with variability in drug response.
Since pharmacogenomics is one of the large-scale "omic" technologies, it can examine the entirety of the genome, rather than just single genes. Pharmacogenomic studies may also examine genetic variation among large groups of people populations , for example, in order to see how different drugs might affect different racial or ethnic groups. Pharmacogenetic and pharmacogenomic studies are leading to drugs that can be tailor-made for individuals, and adapted to each person's particular genetic makeup.
Although a person's environment, diet, age, lifestyle, and state of health can also influence that person's response to medicines, understanding an individual's genetic makeup is key to creating personalized drugs that work better and have fewer side effects than the one-size-fits-all drugs that are common today. For example, the U. Food and Drug Administration FDA recommends genetic testing before giving the chemotherapy drug mercaptopurine Purinethol to patients with acute lymphoblastic leukemia.
Some people have a genetic variant that interferes with their ability to process this drug. This processing problem can cause severe side effects, unless the standard dose is adjusted according to the patient's genetic makeup. See: Frequently Asked Questions about Pharmacogenomics. The rest of those genes tell us everything from our eye colour to whether we're predisposed to certain diseases. A study found that chimpanzees — our closest living evolutionary relatives — are 96 per cent genetically similar to humans.
Cats are more like us than you'd think. A study found that about 90 per cent of the genes in the Abyssinian domestic cat are similar to humans. When it comes to protein-encoding genes, mice are 85 per cent similar to humans. For non-coding genes, it is only about 50 per cent. Thus, chimps and humans may share as many as Chromosomes do not exhibit big structural differences either.
Although there are a number of small chromosomal changes that rearrange the order of genes on regions of those chromosomes, most of these are thought to leave gene function unchanged. It seems likely that the differences between human and chimpanzee phenotypes depend more on subtle regulatory changes more than on the presence of different genes.
For instance, it may be that there are changes in some genes that alter the amount of protein produced by that gene at different stages in the development of a chimp versus a human. Alternatively, there may be small changes to the structures of the proteins from the 1 percent divergence that produce changes in how they interact with other cellular components and therefore subtly alter the pathways in which they are involved. At this point, we do not know which types of changes are responsible for the relatively big differences between chimps and humans.
It is worth noting that individual humans generally differ by about 0. Thus, chimps differ from humans by about fold more, on the average, than humans do from one another. The 0. No two human beings are alike in the traits they possess. Some are tall, others are short; some are stocky, others thin; some are gifted musically, others tone deaf; some are athletic, others awkward; some are outgoing, others introverted; some are intelligent, others stupid; some can write great poetry or music, most cannot.
And so on. To understand our differences, we need to consider not just DNA, but its cellular products as well. This area of study is new, but it is progressing rapidly. The emphasis is changing from DNA sequences to genes. A gene is a stretch of DNA, usually several thousand base pairs long.
The function of most genes is to produce proteins. The genome sequencing project has revealed that we humans have thirty to forty thousand genes. But since a gene often produces more than one kind of protein, sometimes producing different kinds for different body parts, the number of kinds of protein is more like one hundred thousand. We share a number of genes with chimpanzees, genes that make us primates rather than elephants or worms. Evolutionary scientists believe that many of the differences that we observe between ourselves and chimpanzees involve changes in the amount rather than in the nature of gene products.
Human beings and chimpanzees share proteins that produce body hair and brains, but in chimpanzees these proteins produce more hair and less brains.
Why this should be so is still far from being fully understood. But this is a research area that is advancing very rapidly, and there are good genetic leads to be followed up. Of course, not every human difference has a genetic cause. Many are environmental, or are the result of interactions between genes and environment. Even genetically identical twins develop into distinct individuals.
The ability to learn a language is largely innate, built into the nervous system of all normal people, as demonstrated so beautifully in the effortless way in which young children learn to speak. But the particular language any individual learns obviously depends on the social setting. Mozart was a great composer partly because of his genes and partly because of his training.
Ramanujan had a great talent for mathematics, but without his being exposed to a textbook — not a very good one, by the way — he could never have made his astounding discoveries. Michael Jordan has a talent for basketball, but it would never have developed had he grown up among the Inuits.
Just as there are great differences among individuals, there are average differences, usually much smaller, between groups. Italians and Swedes differ in hair color. Sometimes the differences are more conspicuous, such as the contrasting skin color and hair shape of Africans and Europeans.
But, for the most part, group differences are small and largely overshadowed by individual differences. Biologists think of races of animals as groups that started as one, but later split and became separated, usually by a geographical barrier. As the two groups evolve independently, they gradually diverge genetically.
The divergences will occur more quickly if the separate environments differ, but they will occur in any case since different mutations will inevitably occur in the two populations, and some of them will persist. This is most apparent in island populations, where each island is separate and there is no migration between them. Each one has its own characteristic types.
In much of the animal world, however, and also in the human species, complete isolation is very rare. The genetic uniformity of geographical groups is constantly being destroyed by migration between them. In particular, the major geographical groups — African, European, and Asian — are mixed, and this is especially true in the United States, which is something of a melting pot.
But the concept itself is unambiguous, and I believe that the word has a clear meaning to most people. The difficulty is not with the concept, but with the realization that major human races are not pure races. Different diseases are demonstrably characteristic of different racial and ethnic groups. Sickle cell anemia, for example, is far more prevalent among people of African descent than among Europeans.
Obesity is especially common in Pima Indians, the result of the sudden acquisition of a high-calorie diet to which Europeans have had enough time to adjust. Tay-Sachs disease is much more common in the Jewish population. There are other examples, and new ones are being discovered constantly.
The evidence indicating that some diseases disproportionately afflict specific ethnic and racial groups does not ordinarily provoke controversy. Far more contentious is the evidence that some skills and behavioral properties are differentially distributed among different racial groups. There is strong evidence that such racial differences are partly genetic, but the evidence is more indirect and has not been convincing to everyone. To any sports observer it is obvious that among Olympic jumpers and sprinters, African Americans are far more numerous than their frequency in the population would predict.
The disproportion is enormous. Yet we also know that there are many white people who are better runners and jumpers than the average black person. How can we explain this seeming inconsistency?
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