Measurement of inbreeding from the frequency of marriages between persons of the same surname
About: This article is published in Biodemography and Social Biology.The article was published on 1965-12-01. It has received 294 citations till now. The article focuses on the topics: Population & Inbreeding.
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TL;DR: Recent studies involving Y-chromosomal haplotyping and surname analysis are promising and indicate that genealogists of the future could be turning to records written in DNA, as well as in paper archives, to solve their problems.
191 citations
TL;DR: A randomly ascertained sample of males with the surname "Sykes" was typed with four Y-chromosome microsatellites, which points to a single surname founder for extant Sykes males, even though written sources had predicted multiple origins.
Abstract: A randomly ascertained sample of males with the surname "Sykes" was typed with four Y-chromosome microsatellites. Almost half the sample shared the same Y-chromosome haplotype, which has not been observed in control samples either from the same geographic region or from the United Kingdom as a whole. This points to a single surname founder for extant Sykes males, even though written sources had predicted multiple origins. The distribution of other Sykes Y-chromosome haplotypes were not significantly different from those in controls and may be accounted for by the historical accumulation of nonpaternity during the past 700 years, in which case the average rate estimate is 1.3%/generation. If this pattern is reproduced with other surnames, it may have important forensic and genealogical applications.
184 citations
01 Jan 1980
TL;DR: Much of the theory of population genetics is based on the assumption that populations are panmictic, but while this may be nearly true in some instances, most populations of interest exhibit some form of subdivision.
Abstract: Much of the theory of population genetics is based on the assumption that populations are panmictic. While this may be nearly true in some instances, most populations of interest (particularly in man) exhibit some form of subdivision. Most often, spatial subdivision is observable, and population geneticists have studied subdivisions ranging in magnitude from villages to continents. Other types of subdivisions exist as well. Linguistic differences often define barriers to random mating, as do differences in social class, clan or caste membership, and religious affiliation. In addition, various cultural regulations, such as taboos or prescribed mating systems, result in subdivision.
144 citations
TL;DR: Overall, in the Caucasus region, unmatched levels of gene-language coevolution occurred within geographically isolated populations, probably due to its mountainous terrain.
Abstract: We analyzed 40 single nucleotide polymorphism and 19 short tandem repeat Y-chromosomal markers in a large sample of 1,525 indigenous individuals from 14 populations in the Caucasus and 254 additional individuals representing potential source populations. We also employed a lexicostatistical approach to reconstruct the history of the languages of the North Caucasian family spoken by the Caucasus populations. We found a different major haplogroup to be prevalent in each of four sets of populations that occupy distinct geographic regions and belong to different linguistic branches. The haplogroup frequencies correlated with geography and, even more strongly, with language. Within haplogroups, a number of haplotype clusters were shown to be specific to individual populations and languages. The data suggested a direct origin of Caucasus male lineages from the Near East, followed by high levels of isolation, differentiation, and genetic drift in situ. Comparison of genetic and linguistic reconstructions covering the last few millennia showed striking correspondences between the topology and dates of the respective gene and language trees and with documented historical events. Overall, in the Caucasus region, unmatched levels of gene-language coevolution occurred within geographically isolated populations, probably due to its mountainous terrain.
134 citations
TL;DR: Using a computerized genealogical database, inbreeding coefficients were calculated for a sample of 435777 Utah Mormons and Logistic and linear regression analyses of 85 235 marriages demonstrate that consanguinity is significantly dependent upon year of marriage, geographic distance between husband's and wife's birthplaces, and the population size of husband's
Abstract: Using a computerized genealogical database, inbreeding coefficients were calculated for a sample of 435777 Utah Mormons. The population was divided into ten ten-year birth cohorts (1846-1945) and 22 geographic subdivisions in order to assess temporal and spatial variation in inbreeding. The average inbreeding coefficient for this population is 0.000 106. The average within-groups random kinship coefficient is 0.000 312, reflecting consanguinity avoidance. Random kinship matrices were formed by estimating the average kinship within each spatial subdivision and between all pairs of subdivisions. These matrices were compared statistically with kinship matrices previously estimated using migration matrices and isonymy data. The isonymy approach consistently overestimates random and total inbreeding as well as Wright's Fst. This can be attributed primarily to the assumption of monophyletic origin of surnames. The migration matrix method underestimates random inbreeding and Fst. This is due mainly to the assumption that outside immigrants are derived from a genetically homogeneous population. While the absolute values of the kinship coefficients estimated by each method differ substantially, the patterns of between-groups kinship coefficients given by each method are highly congruent. Logistic and linear regression analyses of 85,235 marriages demonstrate that consanguinity is significantly dependent upon year of marriage, geographic distance between husband's and wife's birthplaces, and the population size of husband's and wife's birthplaces.
131 citations
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TL;DR: Page 108, last line of text, for "P/P″" read "P′/ P″."
Abstract: Page 108, last line of text, for "P/P″" read "P′/P″."
Page 120, last line, for "δ v " read "δ y ."
Page 123, line 10, for "4Nn" read "4Nu."
Page 125, line 1, for "q" read "q."
Page 126, line 12, for "q" read "q."
Page 135, line 5 from bottom, for "y4Nsq" read "e4Nsq."
Page 141, lines 8
7,850 citations
6,139 citations
TL;DR: It was found that there is no equilibrium in either case short of complete fixation locally, in spite of the linear increase in number of different ancestors with increasing number of ancestral generations, in contrast to systems (half first cousin or second cousin) in which this increase is more than linear and a steady state is rapidly attained with respect to heterozygosis.
Abstract: Kimura and Crow (1963b) have recently made an interesting comparison between two classes of systems of mating within populations of constant size: ones in which there is maximum avoidance of consanguine mating and ones in which all matings are between close relatives around an unbroken circle. These are illustrated in Figs. 1 and 2 in populations of eight. The rate of decrease of heterozygosis in the former class had, as they note, been found long before to approach 1/(4N) asymptotically with increasing size of population, N (Wright, 1921, 1933a). Two cases with patterns of mating similar to those of Kimura and Crow's second class, except that the matings were between neighbors along infinitely extended lines instead of around a circle, had also been considered in these papers. These systems consisted of exclusive mating of half-sibs or of first cousins, otherwise with a minimum of relationship. It was found that there is no equilibrium in either case short of complete fixation locally, in spite of the linear increase in number of different ancestors with increasing number of ancestral generations. This was in contrast to systems (half first cousin or second cousin) in which this increase is more than linear and a steady state is rapidly attained with respect to heterozygosis. Kimura and Crow were surprised to find that the limiting rates of decrease of heterozygosis in their circular systems are much less than under maximum avoidance approaching [v/(2N + 4)]2 in the case of half-sib matings and [7/ (N + 12)]2 under first-cousin matings with large N. Maxi-
3,305 citations
TL;DR: The effective number of an actual population is defined as the size of an idealized population with the same amount of inbreeding or random gene frequency drift as the population under consideration.
Abstract: : The effective population number can be defined either in terms of the amount of increase in homozygosity (inbreeding effective number) or the amount of gene frequency drift (variance effective number). Under many circumstances these are the same, but not in general. The effective number is considered in terms of an idealized population in which each individual parent has an equal expectation of progeny. The effective number of an actual population is defined as the size of an idealized population with the same amount of inbreeding or random gene frequency drift as the population under consideration. Formulae are given for determining both kinds of effective numbers when the population is monoecious (including self fertilization) and when there are separate sexes. The formulae are summarized along with special cases of interest. (Author)
423 citations