There is a great variation in population growth rates in Asia. There is a great variation in peer comments, displaying a high number of revision-oriented, elaborated formulations. There is a great variation in rainfall received (total amount and distribution) within Chepareria. World J Surg. Oct;41(10) doi: /s A Great Variation in the Reported Incidence of Postoperative Subcutaneous. "Well, I think there is great variation ": a qualitative study of oncologists' experiences and views regarding medical criteria and other factors.
To some extent, this is due to the fact that people's bodies will take up a pharmaceutical substance to varying degrees. Little research has been done in the past to determine whether this is the main reason for the individual differences or one of many. A group of researchers headed by Ruedi Aebersold, a professor of systems biology at ETH Zurich, has now shed some light on the subject in their report published in the journal Cell Systems. The researchers performed detailed measurements of proteins and metabolites in cell culture experiments and succeeded in showing that the differing effects between individuals could not be attributed to a single factor or a few factors.
Instead, the researchers found that many small differences together are responsible for the large variation. Tests with a cholesterol-lowering drug In order to investigate the variable effects of drugs, the scientists analysed cholesterol regulation in four different human cell lines.
They tested how the cells responded differently to various drugs that affect cholesterol levels. In cooperation with ETH professor Uwe Sauer, the researchers used methods from the fields of systems biology, proteomics and metabolomics to measure and compare the concentrations of a very large number of different proteins and metabolites in the cells at specific times.
It turned out that each of the cell lines responded differently to the drugs. Instead, the scientists were able to show that many enzymes and many of the complex biochemical pathways of a cell together contribute to the differences. Oncological applications "Our findings clearly show that simply measuring the amount of drug uptake is not sufficient to understand inter-individual differences in effectiveness, an approach that was typically taken in the past," says Blattmann.
Especially in the case of more advanced medications, there are treatments that only work for a very small group of patients. Genetic variability is a measure of the tendency of individual genotypes in a population to vary become different from one another. Variability is different from genetic diversity , which is the amount of variation seen in a particular population.
The variability of a trait is how much that trait tends to vary in response to environmental and genetic influences. In the study of molecular evolution , a haplogroup is a group of similar haplotypes that share a common ancestor with a single nucleotide polymorphism SNP mutation.
Haplogroups pertain to deep ancestral origins dating back thousands of years. Y-DNA is passed solely along the patrilineal line, from father to son, while mtDNA is passed down the matrilineal line, from mother to both daughter and son.
A variable number tandem repeat VNTR is the variation of length of a tandem repeat. A tandem repeat is the adjacent repetition of a short nucleotide sequence. Tandem repeats exist on many chromosomes , and their length varies between individuals. Each variant acts as an inherited allele , so they are used for personal or parental identification. Their analysis is useful in genetics and biology research, forensics , and DNA fingerprinting.
Short tandem repeats about 5 base pairs are called microsatellites , while longer ones are called minisatellites. The recent African origin of modern humans paradigm assumes the dispersal of non-African populations of anatomically modern humans after 70, years ago. Dispersal within Africa occurred significantly earlier, at least , years ago. The "out of Africa" theory originates in the 19th century, as a tentative suggestion in Charles Darwin's Descent of Man ,  but remained speculative until the s when it was supported by study of present-day mitochondrial DNA, combined with evidence from physical anthropology of archaic specimens.
According to a study of Y-chromosome sequence variation,  human Y-chromosomes trace ancestry to Africa, and the descendants of the derived lineage left Africa and eventually were replaced by archaic human Y-chromosomes in Eurasia.
The study also shows that a minority of contemporary populations in East Africa and the Khoisan are the descendants of the most ancestral patrilineages of anatomically modern humans that left Africa 35, to 89, years ago.
Human genetic diversity decreases in native populations with migratory distance from Africa, and this is thought to be due to bottlenecks during human migration, which are events that temporarily reduce population size. A genetic clustering study, which genotyped polymorphic markers in various African populations, identified six ancestral clusters. The clustering corresponded closely with ethnicity, culture and language. The more closely related the population the higher the percentage of variations.
It is commonly assumed that early humans left Africa, and thus must have passed through a population bottleneck before their African-Eurasian divergence around , years ago ca. The rapid expansion of a previously small population has two important effects on the distribution of genetic variation.
First, the so-called founder effect occurs when founder populations bring only a subset of the genetic variation from their ancestral population. Second, as founders become more geographically separated, the probability that two individuals from different founder populations will mate becomes smaller.
The effect of this assortative mating is to reduce gene flow between geographical groups and to increase the genetic distance between groups. The expansion of humans from Africa affected the distribution of genetic variation in two other ways. First, smaller founder populations experience greater genetic drift because of increased fluctuations in neutral polymorphisms.
Second, new polymorphisms that arose in one group were less likely to be transmitted to other groups as gene flow was restricted. Populations in Africa tend to have lower amounts of linkage disequilibrium than do populations outside Africa, partly because of the larger size of human populations in Africa over the course of human history and partly because the number of modern humans who left Africa to colonize the rest of the world appears to have been relatively low.
The distribution of genetic variants within and among human populations are impossible to describe succinctly because of the difficulty of defining a "population," the clinal nature of variation, and heterogeneity across the genome Long and Kittles Sub-Saharan Africa has the most human genetic diversity and the same has been shown to hold true for phenotypic variation in skull form.
Genetic diversity decreases smoothly with migratory distance from that region, which many scientists believe to be the origin of modern humans, and that decrease is mirrored by a decrease in phenotypic variation. Skull measurements are an example of a physical attribute whose within-population variation decreases with distance from Africa.
The distribution of many physical traits resembles the distribution of genetic variation within and between human populations American Association of Physical Anthropologists ; Keita and Kittles A prominent exception to the common distribution of physical characteristics within and among groups is skin color. This distribution of skin color and its geographic patterning — with people whose ancestors lived predominantly near the equator having darker skin than those with ancestors who lived predominantly in higher latitudes — indicate that this attribute has been under strong selective pressure.
Darker skin appears to be strongly selected for in equatorial regions to prevent sunburn, skin cancer, the photolysis of folate , and damage to sweat glands. Understanding how genetic diversity in the human population impacts various levels of gene expression is an active area of research.
While earlier studies focused on the relationship between DNA variation and RNA expression, more recent efforts are characterizing the genetic control of various aspects of gene expression including chromatin states,  translation,  and protein levels.
The population geneticist Sewall Wright developed the fixation index often abbreviated to F ST as a way of measuring genetic differences between populations. This statistic is often used in taxonomy to compare differences between any two given populations by measuring the genetic differences among and between populations for individual genes, or for many genes simultaneously.
These estimates imply that any two individuals from different populations are almost as likely to be more similar to each other than either is to a member of their own group. They argue the underlying statistical model incorrectly assumes equal and independent histories of variation for each large human population.
A more realistic approach is to understand that some human groups are parental to other groups and that these groups represent paraphyletic groups to their descent groups.
For example, under the recent African origin theory the human population in Africa is paraphyletic to all other human groups because it represents the ancestral group from which all non-African populations derive, but more than that, non-African groups only derive from a small non-representative sample of this African population.
This means that all non-African groups are more closely related to each other and to some African groups probably east Africans than they are to others, and further that the migration out of Africa represented a genetic bottleneck , with much of the diversity that existed in Africa not being carried out of Africa by the emigrating groups. Under this scenario, human populations do not have equal amounts of local variability, but rather diminished amounts of diversity the further from Africa any population lives.
Long and Kittles argued that this still produces a global human population that is genetically homogeneous compared to other mammalian populations.
There is a hypothesis that anatomically modern humans interbred with Neanderthals during the Middle Paleolithic.
In May , the Neanderthal Genome Project presented genetic evidence that interbreeding did likely take place and that a small but significant [ how? It was possibly introduced during the early migration of the ancestors of Melanesians into Southeast Asia. This history of interaction suggests that Denisovans once ranged widely over eastern Asia.
In a study published in , Jeffrey Wall from University of California studied whole sequence-genome data and found higher rates of introgression in Asians compared to Europeans. New data on human genetic variation has reignited the debate about a possible biological basis for categorization of humans into races.
Most of the controversy surrounds the question of how to interpret the genetic data and whether conclusions based on it are sound. Some researchers argue that self-identified race can be used as an indicator of geographic ancestry for certain health risks and medications. Although the genetic differences among human groups are relatively small, these differences in certain genes such as duffy , ABCC11 , SLC24A5 , called ancestry-informative markers AIMs nevertheless can be used to reliably situate many individuals within broad, geographically based groupings.
For example, computer analyses of hundreds of polymorphic loci sampled in globally distributed populations have revealed the existence of genetic clustering that roughly is associated with groups that historically have occupied large continental and subcontinental regions Rosenberg et al. Some commentators have argued that these patterns of variation provide a biological justification for the use of traditional racial categories. Other observers disagree, saying that the same data undercut traditional notions of racial groups King and Motulsky ; Calafell ; Tishkoff and Kidd .
They point out, for example, that major populations considered races or subgroups within races do not necessarily form their own clusters. Furthermore, because human genetic variation is clinal, many individuals affiliate with two or more continental groups.
Thus, the genetically based "biogeographical ancestry" assigned to any given person generally will be broadly distributed and will be accompanied by sizable uncertainties Pfaff et al.
In many parts of the world, groups have mixed in such a way that many individuals have relatively recent ancestors from widely separated regions. Although genetic analyses of large numbers of loci can produce estimates of the percentage of a person's ancestors coming from various continental populations Shriver et al.
Even with large numbers of markers, information for estimating admixture proportions of individuals or groups is limited, and estimates typically will have wide confidence intervals Pfaff et al.
Genetic data can be used to infer population structure and assign individuals to groups that often correspond with their self-identified geographical ancestry. Jorde and Wooding argued that "Analysis of many loci now yields reasonably accurate estimates of genetic similarity among individuals, rather than populations.
Clustering of individuals is correlated with geographic origin or ancestry. The study of 53 populations taken from the HapMap and CEPH data unrelated individuals suggested that natural selection may shape the human genome much more slowly than previously thought, with factors such as migration within and among continents more heavily influencing the distribution of genetic variations.
Forensic anthropologists can determine aspects of geographic ancestry i. Asian, African, or European from skeletal remains with a high degree of accuracy by analyzing skeletal measurements. However, the skeletons of people who have recent ancestry in different geographical regions can exhibit characteristics of more than one ancestral group and, hence, cannot be identified as belonging to any single ancestral group.
Gene flow between two populations reduces the average genetic distance between the populations, only totally isolated human populations experience no gene flow and most populations have continuous gene flow with other neighboring populations which create the clinal distribution observed for moth genetic variation.
When gene flow takes place between well-differentiated genetic populations the result is referred to as "genetic admixture". Admixture mapping is a technique used to study how genetic variants cause differences in disease rates between population.
African-American populations have been the focus of numerous population genetic and admixture mapping studies, including studies of complex genetic traits such as white cell count, body-mass index, prostate cancer and renal disease.
An analysis of phenotypic and genetic variation including skin color and socio-economic status was carried out in the population of Cape Verde which has a well documented history of contact between Europeans and Africans.
The studies showed that pattern of admixture in this population has been sex-biased and there is a significant interactions between socio economic status and skin color independent of the skin color and ancestry. Differences in allele frequencies contribute to group differences in the incidence of some monogenic diseases , and they may contribute to differences in the incidence of some common diseases. To the extent that ancestry corresponds with racial or ethnic groups or subgroups, the incidence of monogenic diseases can differ between groups categorized by race or ethnicity, and health-care professionals typically take these patterns into account in making diagnoses.
Even with common diseases involving numerous genetic variants and environmental factors, investigators point to evidence suggesting the involvement of differentially distributed alleles with small to moderate effects. Frequently cited examples include hypertension Douglas et al. However, in none of these cases has allelic variation in a susceptibility gene been shown to account for a significant fraction of the difference in disease prevalence among groups, and the role of genetic factors in generating these differences remains uncertain Mountain and Risch Some other variations on the other hand are beneficial to human, as they prevent certain diseases and increase the chance to adapt to the environment.
CCR5 gene is absent on the surface of cell due to mutation. Apart from mutations, many genes that may have aided humans in ancient times plague humans today. For example, it is suspected that genes that allow humans to more efficiently process food are those that make people susceptible to obesity and diabetes today.
As a result of variation in frequencies of both genetic and nongenetic risk factors, rates of disease and of such phenotypes as adverse drug response vary across populations. Human genome projects are scientific endeavors that determine or study the structure of the human genome. The Human Genome Project was a landmark genome project. From Wikipedia, the free encyclopedia. Variable number tandem repeat.
Archaic human admixture with modern humans. Race human classification and Race and genetics. American Journal of Human Genetics. First direct whole-genome measure of human mutation predicts 60 new mutations in each of us". By these criteria, 1. Prenatal screening for aneuploidy". The New England Journal of Medicine. European Journal of Human Genetics.
Human Health and the Genome". The Tech Museum of Innovation. National Institute of General Medical Sciences. A dictionary of genetics 7th ed. From individuals to ecosystems 4th ed. International Society of Genetic Genealogy. Retrieved 11 January
Great variation on "surf and turf". - Picture of Kaldera Restaurant, Pella
August 31, The Great Variation. by Karl Smith. This graph rolled across my twitter feed this morning. I can't find the original tweet, but I borrowed the. Same Same But Different, Ko Lanta Picture: Great variation - Check out TripAdvisor members' candid photos and videos. There are great variation in the way people around the world live. The world has seven continents and each continent corresponds a number of.