Gene Flow: Causes and Barriers

Gene Flow: Causes and Barriers Variation of inherited traits in the section of individual organisms over a period of time is referred as evolution. The major renowned sources of variation are gene flow, genetic recombination and mutation. Gene flow that is also acknowledged as gene migrations is the genetic alleles exchange within populations by migration of gametes, spores and individuals of the same species. This is common in species through crossbreeding, migration and cross pollination which yield hybrid organisms. Movement of genes is often carried out by human being and wind. When people move from one town or country to another and carry with them plants to experiment if they can grow in their new location gene variation commence. Differences in gene flow across populations depends on the type of organism, populations of inactive organisms tends to be more isolated from each other than population of actively moving organisms. This paper will examine gene flow as an aspect of evolution biology and provide a d eeper understanding of its benefits to organisms. Mobility in gene flow One of the principal factors contributing the flow of genes between different populations is their movement habit. Plant population compared to animal population appears to be sedentary, hence, animals have high rate of experiencing gene flow. Migration and emigration of populations can reduce genetic differences within that particular group (Beurton, Peter, Raphael Falk et al 224). Through emigration, genes are carried away by the ongoing individuals to a new destination, whilst migration brings on board new genes to an existing gene pool. These processes are activated by perpetual diffusion and mixing of genes of a sexual population. Barriers to Gene Flow Human growth and advancement in technological world has not been without its cons to gene flow. This is a major obstacle to gene flow, especially in its many artificial and permanent development of the landscape. A structure like the Great Wall of China has hinder movement of many organisms and relocation of alleles of genes of indigenous plants population (Lewin 95). Another behavior that prohibits gene flow is the fencing of a game park where insider animals are restricted from meeting others from another park. Vast human progress and occupation can wipe out or partition ecosystems into a desert or secluded islands resulting to lessening genetic variation of the populations imprisoned there. In the efforts to facilitate gene flow scientists are increasingly crafting new ways to connect to these isolated species as away of maintaining viable genetic variation. The other distinguished barriers are the natural barriers that halt or slow the rate of migration of genes among populations . These are oceans, impassable mountains, hills and large and wide deserts that exhibit great challenges for animals movement. This hindrances leads to loss of genes in a population as fertile population are barred from meeting the weak or other strong ones (Beurton et al 124). These barriers in human population have created suspicion and tension among races to an extent of tribal animosity. Conducted studies reveal that sex chromosomes (X and Z chromosomes) are affiliated to reproduction and sex genes (Lewin 88). These genes are a factor in the progression of post zygotic isolation especially in hybrid sterility. It has been noted empirically that strengthening of zygotic isolation does occur in certain conditions. Recombination between alleles is a significant factor that has been identified to be opposing reinforcement. Connections between genes that affect mating and those that affect hybrid fitness plus sex chromosomes have the likelihood of boosting the process of hybridizing species. These ideas fall short of extrapolating whether essential forms of non-adaptive effect of divergence with no gene flow are stagnant or they increase. As a result of this we discover that there exists co evolution of zygotic barriers to the flow of genes. Gene flow in action The lives of species is involves a lot of movements in search of satisfaction and fulfilling hierarchy of needs. Thus, migration has become a significant force of restructuring genetic variation. In the contemporary globalization characterized by wide dispersions of humans in search green pastures and mates gene exchange is take place fast. There are now inter-racial marriages aiding much generating patterns of hereditary variations. Migration can occur to a mass of people due war or search of resources and food or to an individual as a result of displacement or personal drive to explore. Large scale migration of people leads to accumulation of mutations and as a result population diverges as there is genetic drift. Individual movements in a small geographical area enhance genetic variation between populations. These migration behaviors have distinctive effects on population structure with each having its methodological challenges. Gene flow accelerated by intermarriage between national or state communities occurs frequently within a short time period. It remains a challenge to determine temporal control and spatial control of historical human migration. Geographical sampling is a costly exercise, hence, to determine geographic scope of a specific event advanced genotyping technologies are used as they are economical. Determining temporal control which is when gene flow has occurred is even more challenging; DNA studies are examined to come up with resolution pertaining human mobility. New methods are underway to provide conclusive sequential bounds on flow of human genes using genetic data that will be analyzed to show human gene flow. To discover historical movements researchers use genetic markers like mitochondrial DNA and the Y chromosome as they are highly thought to be mainly instructive genetic markers. To study human history using these markers one has to understand that Y chromosome is passed from a f ather to sons while mitochondrial DNA is passed only from mother to off springs. This distinctive mode of transmission makes it easier to study human descent. Due to high rate of random genetic drift in these systems Y chromosome and Mitochondrion DNA have been found to have uncertainty. Their records show biasness towards the sex-specific migration of women and men as they are small loci representing large region of human genetic variations (Slarkin 327). Nowadays, multiple markers can be screened across human genome due to rapid progress in use of genotype technologies. Hence, to determine if two populations have similar genetic variations has become simple. However, it requires advanced modeling and inferential statistics to enumerate and establish the amount of gene flow between them. Gene flow from Neanderthals have made scientist to meditate and compare entire genomes. Complete genome sequence of Neanderthal has been sequenced by some scientist. Previously only mitochondria DNA were accessible from Neanderthal as they occur in numerous copies per cell which make it difficult to mine DNA from primeval remains (Barton Bengtsson 360). In this conducted study there was no trace of gene flow between Neanderthal and human being albeit this research was not conclusive as Mitochondrion DNA could have been mislaid through genetic drift. A complete combination of genome sequence from three Neanderthal creatures has been led by Green and colleagues through use of advanced new technology of sequencing. In contrast to mitochondrion DNA there are data sets that show existence of gene flow from Neanderthal to modern human being. It has been identified that non-African descendant have at least 13 genetic regions that originate from Neanderthal siblings. Since these regions are not present in Africans descent, this is thus a sign to show that gene flow had occurred from Neanderthal to modern people as it is assumed some ancestors had left Africa around 50,000 years to look for other destination in the rest of the world (Servedio Kirkpatrick 766). Conclusion An increase or decrease of a population affects gene pool frequencies as gene flow will have high chance to take place in a densely populated area while there will be minimal changes in a sparsely populated area. For example if all black people were to leave America, the next generation of humans would probably have few or no blacks. This study has revealed that gene flow can occur without migration especially in circumstances where people pays a visit to particular place and mate with natives even though they will eventually go back to their place. In this case, genes are transferred across those populations and the resulting generation is hybridized. Gene flow occurs between species when segment of DNA are carried by viruses in their routine invasion of cells of plants and animals. Although this mechanism of transfer is seldom, there exist documented evidence for some species of microorganisms, mammals, reptiles and insects. Human beings have not been left behind in this process; there is a high probability that 40-50% of DNA sequencing might have been carried out by viruses (Slarkin 420).

Plagiarism and the Internet :: Cheating Education Essays

Plagiarism and the Internet My first memory of plagiarism is from grade school. I can remember having to do book reports. The teacher would always say, "write this report using your own words, do not just copy out of the book". So what did we do, we used a combination of both. In grade school we didn’t realize the seriousness of plagiarism. For the most part we didn’t even really understand what the word meant. It was something the teacher talked about when she assigned essays or book reports. Webster’s dictionary defines plagiarism as this, "to take and use as one’s own the ideas or writings of another." I would suspect plagiarism is as old as the written language. Inevitably, as soon as someone committed their thoughts to paper, someone else read it and used the words to express themselves without giving credit. Plagiarism goes on in all aspects of our society. It does not discriminate. Plagiarism is an issue in our schools, on our college campuses, and in our media. It weaves its thread through our entire culture. The news media and book publishers are all too aware of the nasty concept of plagiarism. Just recently the author J. K. Rowlings of the popular Harry Potter series came under heavy fire. She was accused of stealing another female author’s ideas. It seems in the early 80’s this author published books about the character Larry Potter. Her character names were the same as those in the J. K. Rowling’s series. The differences between the characters in the two series were what the characters actually were. Nimbus is a name used in both series. Nimbus in the Harry Potter series is a broom, however in the other author’s series Nimbus was an actual being. So, there in lies the crux of the matter. Almost every article I read, mentioned the importance of intent. Did the writers style of writing lead him in the direction to naturally produce the work or did the writer intentionally pass off someone else’s work as their own. In the above mentioned case, J. K. Rowlings stated Harry came to her fully formed. She did not willing use the other authors ideas. In the news media pointing the finger of plagiarism at a journalist can set off an event similar to the Salem Witch trials. Plagiarism is taken very seriously in the news media. After all, credibility is at stake, not to mention ratings as well.

Free Essay on Ecology of a Cracker Childhood :: Cracker

Free Essay on Ecology of a Cracker Childhood      Ã‚  Ã‚  Ã‚  Ã‚   By reading Ecology of a Cracker Childhood, it is safe to assume that Janisse Ray, the main character, author, is one who doesn't conform and has a stubborn nature. For instance, when Ray wants to play football with the boys in her class at recess she gets angered when they tell her no she can not play with them; so instead of accepting their reply she jumps in the game anyway and tackles the boy with the football.   The boys angry with the fact that their friend, a guy, got tackled by a girl went chasing after her. Why did Ray feel the need to make a statement by taking down the boy with the football? Perhaps it was her feminist nature, driving her to show the boys that just because she was a female didn't mean that she was not able to do as they did. Whether or not it was feminism, Ray, still has the heart of a revolutionary.      Ã‚  Ã‚  Ã‚  Ã‚   Ray suspected that the boys' rejection was due to the fact that she was a girl, but her suspicions were repudiated when she saw a girl playing with them. The only difference between Janisse and the other girl was that the other girl was not wearing a dress.   The Ray family's religious convictions required the females of the family to wear a dress, providing for the boys uneasiness when it came down to allowing her to play with them. Janisse, dress or not, felt capable of partaking in the sport. It is women like Ray, who will not take no for an answer, that has brought equal rights to their gender in sports, jobs and even around the house.    America was founded, and has been very successful because of people like Ray, who want to leave their backgrounds or use them to learn from them in order to better their lives in the future; the kind of people that will do anything, whether it is leaving their homeland for a foreign soil in search of a new life and freedom, or tackling the boy with the football. Things have been changed, invented, and made better by people that will not take no for an answer. Free Essay on Ecology of a Cracker Childhood :: Cracker Free Essay on Ecology of a Cracker Childhood      Ã‚  Ã‚  Ã‚  Ã‚   By reading Ecology of a Cracker Childhood, it is safe to assume that Janisse Ray, the main character, author, is one who doesn't conform and has a stubborn nature. For instance, when Ray wants to play football with the boys in her class at recess she gets angered when they tell her no she can not play with them; so instead of accepting their reply she jumps in the game anyway and tackles the boy with the football.   The boys angry with the fact that their friend, a guy, got tackled by a girl went chasing after her. Why did Ray feel the need to make a statement by taking down the boy with the football? Perhaps it was her feminist nature, driving her to show the boys that just because she was a female didn't mean that she was not able to do as they did. Whether or not it was feminism, Ray, still has the heart of a revolutionary.      Ã‚  Ã‚  Ã‚  Ã‚   Ray suspected that the boys' rejection was due to the fact that she was a girl, but her suspicions were repudiated when she saw a girl playing with them. The only difference between Janisse and the other girl was that the other girl was not wearing a dress.   The Ray family's religious convictions required the females of the family to wear a dress, providing for the boys uneasiness when it came down to allowing her to play with them. Janisse, dress or not, felt capable of partaking in the sport. It is women like Ray, who will not take no for an answer, that has brought equal rights to their gender in sports, jobs and even around the house.    America was founded, and has been very successful because of people like Ray, who want to leave their backgrounds or use them to learn from them in order to better their lives in the future; the kind of people that will do anything, whether it is leaving their homeland for a foreign soil in search of a new life and freedom, or tackling the boy with the football. Things have been changed, invented, and made better by people that will not take no for an answer.

Genetics Worksheet

Genetic Worksheet Misanna Gordon SCI 230 December 02, 2012 Mitzie Sowell Associate Program Material Genetics Worksheet Review the images below and answer the follow-up questions. Key: Male affected with cystic fibrosis Unaffected male female affected with cystic fibrosis unaffected female Generation I II III IV V Pedigree showing inheritance of cystic fibrosis A Key: Male affected with cystic fibrosis Unaffected male female affected with cystic fibrosis unaffected female Generation I II III IV V Pedigree showing inheritance of cystic fibrosis A Questions: . According to the pedigree, is cystic fibrosis inherited as a dominant or as a recessive traitKey: male with Huntington’s Disease unaffected male female with Huntington’s Disease unaffected female Generation I II III IV V Pedigree showing Inheritance of Huntington’s Disease Key: male with Huntington’s Disease unaffected male female with Huntington’s Disease unaffected female Generation I II III IV V Pedigree showing Inheritance of Huntington’s Disease ? Explain how you made your conclusion using evidence from the pedigree and the principles of genetics.Cystic Fibrosis is considered to be a recessive trait. If a person has only one of the Cystic Fibrosis gene and one of the non-Cystic Fibrosis genes, the person could be a carrier of the Cystic fibrosis gene without having the Cystic Fibrosis disease. Referring back to the mentioning of Mendel, which states that the traits may not show up in a person but still can be passed down to the other generation. Mendel also mentioned that the inheritance of each of the trait can be determined by the genes that can pass down unchanged.Therefore if the Cystic Fibrosis gene is not present, it can become present dependent on the ratio of the amount of genes when it passes down. 2. What would a Punnett square that shows how the son in generation IV (marked with an A) inherited cystic fibrosis look like? [A]a] A [AA] A a] a [Aa] aa] K ey: male with Huntington’s disease unaffected male female with Huntington’s disease unaffected female Generation I II III IV V Pedigree showing inheritance of Huntington’s disease Key: male with Huntington’s disease unaffected male emale with Huntington’s disease unaffected female Generation I II III IV V Pedigree showing inheritance of Huntington’s disease B B Questions: 1. According to the pedigree, is Huntington’s disease inherited as a dominant or as a recessive traitKey: male with Huntington’s Disease unaffected male female with Huntington’s Disease unaffected female Generation I II III IV V Pedigree showing Inheritance of Huntington’s Disease Key: male with Huntington’s Disease unaffected male female with Huntington’s Disease unaffected female Generation I II III IV VPedigree showing Inheritance of Huntington’s Disease ? Explain how you made your conclusion using evidence from the pedigr ee and the principles of genetics. According to the pedigree, it is my belief that the Huntington’s disease is a recessive trait. My reason for the belief is that one of the family members at the beginning of the pedigree was affected by the disease. Also in the third generation, there was no family members affected as well. If the trait was dominant, more family members in the earlier stages of the pedigree would have been affected. 2.What would a Punnett square that shows how the first daughter in generation II (marked with a B) did not inherit Huntington’s disease look like? [B]b] [B]bb] 3. What is the role of chromosomes in the inheritance of genetic traits, such a cystic fibrosis and Huntington’s disease? The genetic traits are carried by the chromosomes. Within the normal cell, the chromosomes each have two parts which is the chromatids. There is also a reproductive cell which is made through the process called meiosis. The meiosis has only one chromatid f or each of the chromosomes. Genetics Worksheet Genetic Worksheet Misanna Gordon SCI 230 December 02, 2012 Mitzie Sowell Associate Program Material Genetics Worksheet Review the images below and answer the follow-up questions. Key: Male affected with cystic fibrosis Unaffected male female affected with cystic fibrosis unaffected female Generation I II III IV V Pedigree showing inheritance of cystic fibrosis A Key: Male affected with cystic fibrosis Unaffected male female affected with cystic fibrosis unaffected female Generation I II III IV V Pedigree showing inheritance of cystic fibrosis A Questions: . According to the pedigree, is cystic fibrosis inherited as a dominant or as a recessive traitKey: male with Huntington’s Disease unaffected male female with Huntington’s Disease unaffected female Generation I II III IV V Pedigree showing Inheritance of Huntington’s Disease Key: male with Huntington’s Disease unaffected male female with Huntington’s Disease unaffected female Generation I II III IV V Pedigree showing Inheritance of Huntington’s Disease ? Explain how you made your conclusion using evidence from the pedigree and the principles of genetics.Cystic Fibrosis is considered to be a recessive trait. If a person has only one of the Cystic Fibrosis gene and one of the non-Cystic Fibrosis genes, the person could be a carrier of the Cystic fibrosis gene without having the Cystic Fibrosis disease. Referring back to the mentioning of Mendel, which states that the traits may not show up in a person but still can be passed down to the other generation. Mendel also mentioned that the inheritance of each of the trait can be determined by the genes that can pass down unchanged.Therefore if the Cystic Fibrosis gene is not present, it can become present dependent on the ratio of the amount of genes when it passes down. 2. What would a Punnett square that shows how the son in generation IV (marked with an A) inherited cystic fibrosis look like? [A]a] A [AA] A a] a [Aa] aa] K ey: male with Huntington’s disease unaffected male female with Huntington’s disease unaffected female Generation I II III IV V Pedigree showing inheritance of Huntington’s disease Key: male with Huntington’s disease unaffected male emale with Huntington’s disease unaffected female Generation I II III IV V Pedigree showing inheritance of Huntington’s disease B B Questions: 1. According to the pedigree, is Huntington’s disease inherited as a dominant or as a recessive traitKey: male with Huntington’s Disease unaffected male female with Huntington’s Disease unaffected female Generation I II III IV V Pedigree showing Inheritance of Huntington’s Disease Key: male with Huntington’s Disease unaffected male female with Huntington’s Disease unaffected female Generation I II III IV VPedigree showing Inheritance of Huntington’s Disease ? Explain how you made your conclusion using evidence from the pedigr ee and the principles of genetics. According to the pedigree, it is my belief that the Huntington’s disease is a recessive trait. My reason for the belief is that one of the family members at the beginning of the pedigree was affected by the disease. Also in the third generation, there was no family members affected as well. If the trait was dominant, more family members in the earlier stages of the pedigree would have been affected. 2.What would a Punnett square that shows how the first daughter in generation II (marked with a B) did not inherit Huntington’s disease look like? [B]b] [B]bb] 3. What is the role of chromosomes in the inheritance of genetic traits, such a cystic fibrosis and Huntington’s disease? The genetic traits are carried by the chromosomes. Within the normal cell, the chromosomes each have two parts which is the chromatids. There is also a reproductive cell which is made through the process called meiosis. The meiosis has only one chromatid f or each of the chromosomes.

Century medical history

Century Medical History Report The 18th century consisted of a lot of social and political events. Some of the social happenings that occurred In this century were the French and Indian War, the African slave trade, and many developing Ideas and Inventions were growing throughout the world. Many medical happenings were present as well. Smallpox was the mall widespread disease that affected the whole world. Inventions and discoveries were made to solve problems or mysteries. An Important person wasEdward Jennet, who â€Å"discovered† a smallpox vaccination. He did not actually Invent It, because it had already existed. She ran an experiment on an eight year old boy to test the smallpox vaccine. He did this by giving him cowpox first which served as a immunization. Joseph Priestley was an important figure in the 18th century. He discovered the now called element oxygen. Before his discovery, people did not understand what air wasÃ'› or what it was made of. He also was a resear cher, Philosopher and a Chemist. Benjamin Franklin invented the bifocals, although he was greatly known for his work in electrical theory.He established laws on how electricity operates, how to store and use it. He is also famous for his experiment with the kite and key. Rene Lancer invented the Stethoscope. With this he investigated sounds made by the heart and lungs, and compared it to his diagnosis he got from autopsies. He also wrote the first descriptions of bronchitis's and cirrhosis and also classified lung conditions like pneumonia, pleurisy and emphysema. Lastly, John Hunter was a surgeon of the 18th century and is now known as founder of â€Å"scientific surgery. † He made many advances in surgical procedures, while teaching anatomy and surgery.He also first documented reports on â€Å"tube feeding. † By gyring The 18th century consisted of a lot of social and political events. Some of the social happenings that occurred in this century were the French and In dian War, the African slave trade, and many developing ideas and inventions were growing the main widespread disease that affected the whole world. Inventions and discoveries were made to solve problems or mysteries. An important person was Edward Jennet, who â€Å"discovered† a smallpox vaccination. He did not actually invent it, immunization. Joseph Priestley was an important figure in the 18th century. He

Principles of Economic Essay Example | Topics and Well Written Essays - 3500 words

Principles of Economic - Essay Example If both countries are closed economies, i.e., they do not participate in any trade then both countries will produce both goods by allocating half of their resources to each of the goods, tomatoes and clothes in our case. Consider the hypothetical table below: They cannot produce entire amounts of both goods at the same time. However, participating in international trade and specialization can help increase their production possibilities. Since Pakistan is better at cloth production while Germany is better at tomatoes production, Pakistan is said to have an absolute advantage in cloth production and Germany in tomatoes production. Therefore, common sense suggests that each should specialize in the good in which they have an absolute advantage and as a result, each of them would be better off than they were before. This means that Pakistan should produce 400 clothes and no tomatoes and Germany should produce 400 tomatoes and no clothes. Therefore, Pakistan can now import 200 tomatoes from Germany while Germany can import 200 clothes from Pakistan, thereby each of them realizing a gain of 150 from international trade and specialization. Clearly there is a gain from international trade and specialization in the form of increased production possibilities. ... Therefore, Pakistan can now import 200 tomatoes from Germany while Germany can import 200 clothes from Pakistan, thereby each of them realizing a gain of 150 from international trade and specialization. Cloth Tomatoes Total production (without trade) 250 250 Total production (with trade) 400 400 Clearly there is a gain from international trade and specialization in the form of increased production possibilities. However, even when, for instance, Germany has an absolute advantage in the production of both tomatoes and clothes, participating in international trade and specialization can increase its production possibilities and increase world trade. The theory of comparative advantage says that it should specialize in those goods which it can produce with relatively greater efficiency and import the other. However, we must remember that the above was based on two countries and two products only. In the real world, there are many products and countries involved. However, this model can be extended to include any number of countries or products. Other assumptions are also involved such as production costs are constant and there are no restrictions on international trade. In reality, this is not true. Nevertheless, we can conclude that international trade and specialization can increase world trade through the theories of absolute and comparative advantage. Q2 (a) (i) Price of Mangoes - $ / kg Quantity Demanded - 000/kg Quantity supplied-000/kg $6.00 220 400 $5.50 240 360 $5.00 260 320 $4.50 280 280 $4.00 300 240 $3.50 320 200 $3.00 340 160 Equilibrium quantity= 280000

Napoleonic Wars Essay Example | Topics and Well Written Essays - 2000 words

Napoleonic Wars - Essay Example By the end of 1813 that mythology of invincibility had disappeared, mainly due to the disastrous campaign in Russia. The background to this campaign was the simplification of national borders and the increase of nationalist sentiments that had at least been catalyzed by French ideas that had developed since the French Revolution. Thus Napoleon's own use of nationalistic sentiment was causing resentment against French domination within other countries (Schom, 1998). This was perhaps not the best time to launch a campaign against a formidable enemy that would take Napoleon far from those countries that were starting to stir against French imperialism. But as with many military commanders both before and since, Napoleon had started to believe in his own legend, and it would eventually lead to his downfall (Gengembre, 2003). In the spring of 1812 Napoleon began to mass his troops in Poland, that was currently under French rule. This was clearly an attempt to intimidate Alexander, who had been showing an increasing tendency not to trust he official alliance between France and Russia. By the summer of 1812 about 453,000 men, probably the largest armed force ever gathered in one place up until that time, had been brought together in Poland. Napoleon called it his Grande Armee, and its message to the Russians was quite clear. The Russians, perhaps aware that the hu... 130 years later to Hitler, Napoleon appeared to be advancing with miraculous speed, but in fact the Russians were adopting a "scorched earth policy" in which they destroyed anything of value before retreating in front of the French forces. This meant that the French could not gather together provisions and supplies that would be needed in the coming winter. Drawn to the centre of Russia, with the supposed prize of Moscow, as a moth is to a light, Napoleon advanced through the country until he met the Russian forces at the Battle of Borodino on September 7th, 1812. This was a bloody, violent battle, but was inconclusive as to its result. Even though neither side had gained a clear victory, Napoleon carried on advancing and entered Moscow on about September 14th. The Russians had deserted the city, Alexander would not meet with Napoleon to discuss terms for the Russian "surrender" and much of the city burned down within days of Napoleon's arrival.Napoleon had won perhaps the most Pyrrhic victory of all time: he was faced with a stalemate in which he had taken Moscow, but could not sustain it because his supply lines were desperately strained and he needed to retreat before the full onset of winter. One of the great mistakes that Napoleon had made was having neither enough nor the correct quality horses. In the retreat many of the cavalry had to kill their horses in order to eat them. Many others died of cold, disease and starvation. This meant that Napoleon's forces could receive neither food supplies nor reinforcements nor supplied for their weapons. The French lost about 200,000 horses in the campaign, as well as 1,000 artillery pieces. These were large losses that Napoleon could not really afford considering the various campaigns that were to come. He had also