how does our DNA change through evolution???
600557
Ultimately all changes in DNA sequence across all living organisms are the result of mutations.  Essentially, the copying process went wrong somewhere along the line and generated a change.  These may occur as a result of many factors.\n\n1.) Substitutions are changes in single bases.  A becomes T for example.  In a large fraction of cases, this will lead to  a change in the amino acid, which in turn changes the protein.\n\n2.) Indels (insertion/deletion events) will add or subtract DNA.  During replication, a segment of DNA may be added or removed leading to a change.  It is also possible that DNA becomes damaged or lost and that change is passed on to future generations.\n\n3.) Recombination can lead to novel arrangements of existing strands of DNA.  It can also occur improperly and generate change (often through indels).\n\n4.) Chromosomal rearrangement.  If chromosomes break they may reattach elsewhere, become a whole new chromosome, or lose parts entirely.  This can lead to moving an allele into a completely new gene environment.  The protein itself may not change, but the expression of the protein might.\n\nFinally, natural selection and random effects (such as bottlenecks) will affect the gene frequencies.  Sometimes these will allow for new interactions of genes.
119623
In nature, living things evolve through changes in their DNA. In an animal like a chicken, DNA from a male sperm cell and a female ovum meet and combine to form a zygote -- the first cell of a new baby chicken. This first cell divides innumerable times to form all of the cells of the complete animal. In any animal, every cell contains exactly the same DNA, and that DNA comes from the zygote. \n\nChickens evolved from non-chickens through small changes caused by the mixing of male and female DNA or by mutations to the DNA that produced the zygote. These changes and mutations only have an effect at the point where a new zygote is created. That is, two non-chickens mated and the DNA in their new zygote contained the mutation(s) that produced the first true chicken. That one zygote cell divided to produce the first true chicken. \n\nPrior to that first true chicken zygote, there were only non-chickens. The zygote cell is the only place where DNA mutations could produce a new animal, and the zygote cell is housed in the chicken's egg. So, the egg must have come first.\n\nVirginia Kelly\n\nTo be ...
905240
Alterations to DNA are called mutations, and they can result in the formation of new characteristics that are heritable, or capable of being inherited.\n\nEvery cell in the body of every living organism contains DNA in threadlike structures called chromosomes. Stretches of DNA that hold coded instructions for the manufacture of specific proteins are known as genes, of which the human race has approximately 40,000 varieties. If the DNA of a particular gene is altered, that gene may become defective, and the protein for which it codes also may be missing or defective. Just one missing or abnormal protein can have an enormous effect on the entire body: albinism, for instance, is the result of one missing protein.\n\nMutations also can be errors in all or part of a chromosome. Humans normally have 23 pairs of chromosomes, and an extra chromosome can have a tremendous negative impact. For example, there should be two of chromosome 21, as with all other chromosomes, but if there are three, the result is Down syndrome. People with Down syndrome have a unique physical appearance and are developmentally disabled. Nor is an extra chromosome the only chromosomal abnormality that causes problems: if chromosomes 9 and 22 exchange materials, a phenomenon known as translocation, the result can be a certain type of leukemia. Down syndrome also results from translocation.\n\nGerminal mutations are those that occur in the egg or sperm cells and therefore can be passed on to the organism's offspring. Somatic mutations are those that happen in cells other than the sex cells, and they cannot be transmitted to the next generation. This is an important distinction to keep in mind in terms of both the causes and the effects of mutation. If only the somatic cells of the organism are affected, the mutation will not appear in the next generation; on the other hand, if a germinal mutation is involved, what was once an abnormality may become so common in certain populations that it emerges as the norm.\nEvery single human trait—blue eyes, red hair, cystic fibrosis, a second toe longer than the big toe, and so on—is the result of some genetic mutation somewhere back down the line. Traits that are shared by all people must have arisen long ago, while other traits occur only in certain populations of people. Traits may be as innocuous as eye color or hair texture or as grave as a shared tendency toward a particular disease. Cystic fibrosis, for instance, is most common in people of northern European descent, while sickle cell anemia (see Amino Acids) occurs frequently in those of African and Mediterranean ancestry. A fatal disorder known as Tay-Sachs is found primarily in Jewish people whose ancestors came from Eastern Europe. In many cases, the particular mutation, while harmful in one regard, proved to be a useful one for that population. We know, for example, that while two copies of the mutant sickle cell anemia gene cause illness, one copy confers resistance to malaria—a very useful trait to people living in the tropics, where malaria is common.\n\nThe Pima "fat-Storage Mutation."\n\nResearchers have noted a high incidence of obesity among the Pima, a Native American tribe whose ancestral homeland is along the Gila and Salt rivers in Arizona. The Pima tend to eat a diet that is no more fatty than that of the average American—which, of course, means that it is plenty fatty, complete with chips, bologna, ice cream, and all the other high-calorie, low-nutrient foods that most Americans consume. But whereas the average American is over-weight, the average Pima is more dramatically so. This suggests that long ago, when the ancestors of the Pima had to face repeated periods of famine in the dry lands of the American Southwest, survival favored the individual or individuals who had a mutation for fat storage. It so happens that today, there is more than enough food at the local supermarket, but by now the Pima as a group has the fat-stora
417879
This question appears regularly in the question file, so let's take a shot at it. \n\nIn nature, living things evolve through changes in their DNA. In an animal like a chicken, DNA from a male sperm cell and a female ovum meet and combine to form a zygote -- the first cell of a new baby chicken. This first cell divides innumerable times to form all of the cells of the complete animal. In any animal, every cell contains exactly the same DNA, and that DNA comes from the zygote. \n\nChickens evolved from non-chickens through small changes caused by the mixing of male and female DNA or by mutations to the DNA that produced the zygote. These changes and mutations only have an effect at the point where a new zygote is created. That is, two non-chickens mated and the DNA in their new zygote contained the mutation(s) that produced the first true chicken. That one zygote cell divided to produce the first true chicken. \n\nPrior to that first true chicken zygote, there were only non-chickens. The zygote cell is the only place where DNA mutations could produce a new animal, and the zygote cell is housed in the chicken's egg. So, the egg must have come first.
1135377
You have to look at evolution as a series of slight beneficial changes that are passed down through generations.  The steps from single to double circ are unknown to me, but it is more than a single big jump.
1098346
Truth is, we are still Evolving, but evolution is a slow process barring environmental disasters (think Chernobyl or the meteor impact that supposedly wiped out the dinosaurs).\n\nThe last two big DNA changes with humanity occurred 10,000 and 4,000 years ago, if _Science News_ articles are to be believed.  They were mainly dietary, involved changes to the digestive system so that mannose (tree nut sugars), lactose (milk sugars) and other plant and animal simple sugars could be digested by the human digestive system.\n\nAnd this was in the absence of either civilization (which may or may not slow down pro-survival pressures) or pollution (which may speed them up).\n\nBefore that?  You have to look at some of the dietary and bloodstream changes between ancestral Africans (bitter-taster versus non-taster, and the platelet changes responsible for sickle-cell anemia) and others that occurred in part to confer extra resistance to malaria.\n\nNot that any of this matters if you refuse to believe in physical evidence gathered by genetic research or paleontology....if you willfully refuse to heed reason nothing *will* convince you.  Not a flame, a statement of human nature, really, sad as it is.
478754
You can say that but simply change in environment isn't responsible. Evolution is combined result of various processes such as struggle for existence, hereditary variations, and most importantly gene mutations which are sudden changes in Base sequence in DNA
639448
thousands....changing always due to evolution
613
Interestingly phrased.\n\nYes, I would say that DNA is the map from where we are coming from. Researchers are using DNA and the relative similarities of certain sequences to deduce just how long ago we diverged from previous forms.\n\nWhat I mean by that: evolutionarily speaking, everything living on earth today can be traced back to a common ancestor (LUCA - Last Universal Common Ancestor). The bigger the difference in the sequences of two species DNA, the longer ago we diverged from that common ancestor and the less related the two organims are to one another -- meaning there are more intermediate organisms between their current status and the ancient ancestor shard by the two.\n\nWe can use DNA not just to illucidate species broad histories, but individual histories too. We have a very unique piece of DNA in our cells. It is contained in our mitochandria. Mitochandria are little energy plants in our cells. The DNA in mitochandria, unlike the rest of our DNA, as we know it, is passed down only from our mothers. So, based on that, this DNA is less diverse. Any differences in this DNA has to come from mutations. Because the mutation rate is relatively slow, there are key "markers" that have appeared from time to time in specific subgroups of humans over time. So the markers you contain in your mitochandrial DNA are indicative of where which subgroup you are a decenent of. These subrgroups can be indicative of races, but as the more information we collect on the various markers from around the world, we'll be able to determine specific regions from which your ancestors lived and migrated to throughout history.\n\nAs far as a map to where we are going, I would say that DNA is that too, but that is less able to be predicted. Our DNA will definitely determine how our species continues to evolve. Let me give you an example. Let's say that this bird flu pandemic that the media has been stressing over the past 6 months actually does happen sometime in the future. An individuals ability to survive such a pandemic will be directly linked to their specific genetic sequence. Some will be innately immune to infection and thus will probably survive the pandemic. Others will not be so lucky. If the speculation is true and hundreds of millions of people do die, their genetic makeup will be eliminated -- thus those genes that make up those people will be removed from the general gene pool. The remainder of people will determine the fate of humankind. If another pandemic was to follow years down the road and the genes that were left over were succeptble to that infection, it could mean the end of the human race. More than likely though, there will always be some subset of the population whose genes allow for survival. From there, the future of humans depends on how overall fit those genes are.
384649
mutation- it is the heritable change in the genetic material ie DNA of an organism.it can involve changes in gametes (germline mutations) and changes in body cells (somatic mutations). \n\ncheck out this site for info:
498613
In nature, living things evolve through changes in their DNA. In an animal like a chicken, DNA from a male sperm cell and a female ovum meet and combine to form a zygote -- the first cell of a new baby chicken. This first cell divides innumerable times to form all of the cells of the complete animal. In any animal, every cell contains exactly the same DNA, and that DNA comes from the zygote. Chickens evolved from non-chickens through small changes caused by the mixing of male and female DNA or by mutations to the DNA that produced the zygote. These changes and mutations only have an effect at the point where a new zygote is created. That is, two non-chickens mated and the DNA in their new zygote contained the mutation(s) that produced the first true chicken. That one zygote cell divided to produce the first true chicken. Prior to that first true chicken zygote, there were only non-chickens. The zygote cell is the only place where DNA mutations could produce a new animal, and the zygote cell is housed in the chicken's egg. So, the egg must have come first.
20815
You've probably heard the fact that our DNA is 98% the same as that of a monkey, what many people don't know is that our DNA is also about 80% the same as that of a fruit fly. Dog DNA probably comes in somewhere in between. I don't think anyone has ever done a study on that though.
625147
Is possible, but the most interesting thing is that we are alein too. Our DNA could not evolutioned in the time that we knows. The scientist and co-discoverer of the structure of the DNA molecule, Francis Crick says that our DNA came altrhough artificial mechanism to the earth because the structure is so complicated and a meteor would have damage it. In the OT God is talking so strange, like a Human Being, he feel emotions, good and destructive emotions, obviously he could to be not the real God or the creator of the Universe, may be He was a Super Natural being showing to us the real path to the S`piritual Evolution. May be He was the responsible of many strange things that the cience only could to explain with the Super Natural Being Intervention. We knows now that we was guided by a being that could to make many things in the earth like the big structures and complicated engginner or advanced technology found in the History in many cultures who said that thir Gods could to be seen.\n\nIs possible it if we take the references in the Zecharia Sitchin studies when the cultures show us the relationship between God and the Human Beings. Interesting parts like in Genesis 6 show us that the "Angels" had sex with human beings having physical body, knowing that the Angels like our Lord Jesus Christ says can not to get married. Is so interesting because may be Jesus Christ came to the heart from the real God, changing the old concepts about God and the old laws. Why Jesus would change the laws? What relationship could to have Jesus with the God in the old testament? Why the law changed so drastically? May be the Super Natural being that was trying to show us the real path to the spirituality fails in his try and Jesus, may be like a superior lader or a real representation from God came to repair the wrong concept created before. With JesusChrist all humans beings could to be saved, not only the Jews people, all world could to be saved.\n\nFor this rason the God in OT could to be from other reality, other dimenssion, not from the other planet, because he really was a creator and a Super natural being and is a big question that probably nobody will answer until the ned of the time.
789827
We are basically all the same.  Those small differences in DNA as a result of mutation (genetics) are what make us feel (and look) so different from one another.  But remember how tiny those DNA particles are...
96823
1. Changes in allelic frequencies over time\n2. Change in a lineage of populations between generations
395275
In nature, living things evolve through changes in their DNA. In an animal like a chicken, DNA from a male sperm cell and a female ovum meet and combine to form a zygote -- the first cell of a new baby chicken. This first cell divides innumerable times to form all of the cells of the complete animal. In any animal, every cell contains exactly the same DNA, and that DNA comes from the zygote.\n\nChickens evolved from non-chickens through small changes caused by the mixing of male and female DNA or by mutations to the DNA that produced the zygote. These changes and mutations only have an effect at the point where a new zygote is created. That is, two non-chickens mated and the DNA in their new zygote contained the mutation(s) that produced the first true chicken. That one zygote cell divided to produce the first true chicken.\n\nPrior to that first true chicken zygote, there were only non-chickens. The zygote cell is the only place where DNA mutations could produce a new animal, and the zygote cell is housed in the chicken's egg. So, the egg must have come first.
978981
In biology, evolution is the change in the heritable traits of a population over successive generations, as determined by shifts in the allele frequencies of genes. Over time, this process can result in speciation, the development of new species from existing ones.