The Equidistance Index of Population Structure
نویسندگان
چکیده
Measures of population differentiation, such as FST, are traditionally derived from the ratio of genetic diversity within and between populations. However, the emergence of population clusters from multilocus analysis is a function of genetic structure (departures from panmixia) rather than diversity. If the populations are close to panmixia, slight differences between the mean pairwise distance within and between populations (low FST) can manifest as strong separation between the populations, thus population clusters are often evident even when the vast majority of diversity is partitioned within populations rather than between them. Moreover, because FST utilizes the mean rather than deviations from the mean, it does not directly reflect the strength of separation between population clusters. For any given FST value, clusters can be tighter (more panmictic) or looser (more stratified), and in this respect higher FST does not always imply stronger differentiation. In this study we propose substituting the mean in the FST equation with the standard deviation, thereby deriving a novel measure of population separability, denoted EST, which is more consistent with clustering and classification. To assess the utility of this metric, we ranked various human (HGDP) population pairs based on FST and EST and found substantial differences in ranking order. In some cases examined, most notably among isolated Amazonian tribes, EST ranking seems more consistent with demographic, phylogeographic and linguistic measures of classification compared to FST. Thus, EST may at times outperform FST in identifying evolutionarily significant differentiation.
منابع مشابه
The Genetic Equidistance Result of Molecular Evolution is Independent of Mutation Rates.
The well-established genetic equidistance result shows that sister species are approximately equidistant to a simpler outgroup as measured by DNA or protein dissimilarity. The equidistance result is the most direct evidence, and remains the only evidence, for the constant mutation rate interpretation of this result, known as the molecular clock. However, data independent of the equidistance res...
متن کاملEquidistant Intervals in Perspective Photographs and Paintings
Human vision is extremely sensitive to equidistance of spatial intervals in the frontal plane. Thresholds for spatial equidistance have been extensively measured in bisecting tasks. Despite the vast number of studies, the informational basis for equidistance perception is unknown. There are three possible sources of information for spatial equidistance in pictures, namely, distances in the pict...
متن کاملGenetic diversity analysis and population structure of some Iranian Fenugreek (Trigonella foenum-graecum L.) landraces using SRAP Markers
Fenugreek is one of the important edible and medicinal vegetables that have a long history of cultivation and consumption. Characterize the extent of the genetic diversity among landraces will provide a good context for future breeding programs and genetic resource preservation. Genetic diversity and population structure of 88 individuals of eight landraces of Iranian fenugreek evaluated based ...
متن کاملAnalysis of genetic diversity, phylogenetic relationships and population structure of Arasbaran cornelian cherry (Cornus mas L.) genotypes using ISSR molecular markers
Cornelian cherry (Cornus mas L.), considered as the ancestor of cultivated trees in Arasbaran region, is a medicinally and economically plant species. However, little is known about genetic diversity, breeding programs, and population structure of this species in mentioned region. Keeping this in view, the main objectives of present study were to analysis the genetic diversity, phyloge...
متن کاملOn equidistance graphs
Motivated by a problem concerning some combinatorial designs, we introduce the concept of an i-equidistance graph as a graph Γ with the property that its distance-i graph Γ(i) has the same number of edges as it. In the special case where Γ is i-equidistance for every i not exceeding its diameter we say that Γ is an equidistance graph. We give several examples and properties and we propose some ...
متن کاملEvaluation of Population Structure and Estimation of Genetic Parameters in Breeding Lines and Landraces Populations of Durum Wheat Using ISSR Markers
Evaluation of genetic diversity is the key principal for plant breeding, providing an opportunity to discover novel characters and alleles for breeders. In the present study, 69 durum wheat genotypes were investigated for genetic diversity using several inter-simple sequence repeat (ISSR) markers. Sixteen ISSR primers amplified a total of 163 fragments, which out 160 fragments were polymorphic....
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 2015