Dynamics Of Founder Effect Essay, Research Paper
An Introduction Into the Dynamics of the Founder Effect
The Human Species
MWF 3:00 p.m.
Populations are divided by geographic boundaries, confining a specific region/group of people to share and distribute its genetic traits within themselves without outward influence. The size of these populations is dependant upon whether certain mountains, rivers, deserts, oceans, or other extreme geographical, cultural, or technological conditions determine the tendency for isolation or migration. Most modern populations were originally settled by a relatively small handful of people that for whatever reason migrated to a new uninhabited area, and then multiplied. The genetic code of those founding individuals largely determines the genetic code of future generations, making that area distinctive having it’s future generations genetic code modeled after the original founders.
Analyzing the founders of populations requires written or physical evidence to identify any possible founder of a population. So to analyze modern founding fathers is relatively easier in comparison to older founding fathers because of a lack of physical evidence for older populations. For a recently founded population such as the French settlers that migrated to the Chicoutimi region of Quebec, Canada in the 1940’s there is a collection of written knowledge about it’s inhabitants over that time. That information can identify the specifics person/persons that might have founded that population. Other populations that we have a large collection of knowledge regarding its founders include white Australians, African-Americans, as well as certain Caribbean populations. In contrast, trying to determine the founding fathers whom settled North America from Asia about fifteen thousand years ago is much more difficult because there is so little recorded evidence and knowledge of that time period. This makes it difficult to determine the founders of the large populations we know today. Equatorial Africa was occupied by mostly Bushmen and Pygmies until about two thousand years ago, when the Bantu speaking people of the Congo region developed agriculture, iron, and domesticated animals. Following those advances the small number of Bantu multiplied until they overran half the African continent, pushing the Pygmies and Bushmen into areas unsuitable for farmland. The Bantu peoples thereby founded the entire gene pool of subequatorial Africa anew a mere 2,000 years ago. Europe’s founding fathers came largely within two migrations: one being farmers form the Near East about eight thousand years ago settling largely along the Mediterranean; the second being from Southern Russia about six thousand years ago populating northern and western Europe.
The genetic traits of the founders of a population can be positive, negative, or neutral. Negative traits usually destroy founding populations unless the people with those traits die off. If not, then the entire population could die depending upon how severe the trait was, and if it was dominant or recessive. Something such as an enzyme or respiratory deficiency would be considered a negative trait. If the trait were dominant, than it would appear in all offspring of the parent and result in either the death of those people having that trait in the population, or perhaps even the entire population. If a negative trait were recessive than it’s effects would be less exhibited because it would take two carriers to pass the trait on, and even then the chances of having a homozygous recessive genetic code would be only 1:4 for heterozygous parents. (The chances of dominant genetic trait being exhibited in subsequent offspring whose parents were heterozygous both had the trait would be 3:4) A recessive negative trait will usually linger for more generations than a dominant one because it “hides” away, and it’s negative effects will be considerably less than a dominant allowing for the growth of a population. Most genetic traits of large populations are either positive or neutral; the original founder’s providing distinct traits that did not inhibit future growth. Neutral traits do not benefit or inhibit, such traits include eye color, fingerprint patterns, and facial shape. In Europeans, fingerprint loops are more common than whirls, while in Australian aborigines whirls are more common than loops. An example of a positive trait would be a resistance against malaria. Certain populations of the world each have their own unique genetic trait that changes the composition of their hemoglobin. In Africa it is Hb s, in Southeast Asia it is Hb E. Each of these traits are recessive and when homozygous recessive have harmful effects upon the person, when heterozygous they provide resistance to malaria. Because malaria is such a harmful disease in those areas, the people that it saves from malaria is usually higher than the number that die from having homozygous recessive genes for that trait.