scholarly journals Measuring Selection Intensities Among Kolam Population: Manifested through Differential Fertility and Differential Mortality

2019 ◽  
pp. 35-48
Author(s):  
Bharathi K
Keyword(s):  
Andhra Pradesh ◽  
Differential Mortality ◽  
Selection Intensity ◽  
Differential Fertility ◽  
Total Index ◽  
Postnatal Mortality ◽  
History Of ◽  
Telangana State ◽  
Selection Intensities ◽  
Modified Formula

The objective of the study is to understand the selection intensities among Kolam, a particularly vulnerable tribal group (PVTG) of Adilabad district of Telangana State, India. Two prominent methods were employed to understand the intensities by using Crow’s index and modified formula as given by Johnston and Kensinger’s method. The intensities are computed on the basis of the reproductive history of mother with completed fertility and the results were compared with the available works on populations belonging to Andhra Pradesh, Telangana and India. The Crow’s total index (II) value was found to be 0.3863. The mortality (Im) component was found to be 0.2151 while fertility (If) component was found to be 0.1712. The contribution of mortality component is greater than that of fertility component among the present studied population using Crow’s index. According to Johnston and Kensinger, the total index (II) was found to be 0.6017. Fertility component was found to be 0.2368, prenatal mortality component (Ime) and postnatal mortality component (Ime/Pb) where observed to be 0.0675 and 0.0933 respectively. Therefore, it is clear from the results that postnatal mortality contributes more than prenatal mortality for selection, i.e., Johnston and Kensinger’s Index (0.6017) contributes more towards selection intensity than Crow’s index (0.3863). Natural selection takes place when there is variability of fitness observed through the differences in fertility and mortality in any population.

ABO BLOOD GROUPS AND COMPLETED REPRODUCTIVE PERFORMANCE OF RURAL HARYANAVI COUPLES: ANALYSING MEASURES OF SELECTION INTENSITIES

2004 ◽  
Vol 36 (6) ◽  
pp. 633-646 ◽  
Author(s):  
KRISHAN SHARMA ◽  
RAJNI KAPOOR
Keyword(s):  
Reproductive Performance ◽  
Differential Mortality ◽  
Present Sample ◽  
Live Births ◽  
Postnatal Mortality ◽  
Pregnancy Wastage ◽  
Selection Intensities ◽  
One Year ◽  
The Individual ◽  
Living Children

The possible differential effects of ABO blood group materno-paternal (fetal) incompatibility on completed reproductive performance were investigated on a sample of 100 couples (100 fathers and 100 mothers) from three villages in the Jind district of Haryana state, India. The average number of live births per mating couple was slightly higher for the incompatible matings (5·32) than the compatible ones (5·05). This advantage was offset by higher postnatal mortality in the former. Consequently, the average number of living children in the compatible matings (4·64) was higher than in the incompatible ones (4·18). With reference to individual ABO matings, the index of relative fertility (Irf) was the highest in A×AB followed by B×A type of incompatible matings. No decrease in live births in O×A and O×B incompatible matings was observed compared with their reciprocal compatible ones, i.e. A×O and B×O matings, as has been hypothesized in previous studies. The total pregnancy wastage was substantially higher in ABO-incompatible matings (24·59%) than compatible matings (8·45%). About 71% of the postnatal deaths took place within one year of the birth in the case of incompatible matings compared with 50% in the case of compatible matings. The study supports the hypothesis that selection is operative at the ABO locus as revealed by the measures of selection intensity. The loss of fitness in the present sample was associated with differential mortality. There were no differences in the proportions of average number of male live births in the compatible (0·55) and incompatible matings (0·58). However, in the individual mating types, there was some evidence of higher or lower proportions of male live births.

scholarly journals Selection intensity and its opportunity among the Santal women of Keonjhar, Odisha, India

2015 ◽  
Vol 1 (4) ◽  
pp. 203
Author(s):  
Subal Das ◽  
Binoy Kumar Kuiti ◽  
Kaushik Bose
Keyword(s):  
Natural Selection ◽  
Selection Intensity ◽  
Intensity Index ◽  
It Value ◽  
Fertility Index ◽  
Total Index ◽  
Mortality Index ◽  
Postnatal Mortality ◽  
Total Selection

Present study dealt with the opportunity of natural selection using Crows index and Johnston and Kensinger's Index among the Santal womens of Keonjhar, Odisha, India. Mortality index (Im), Fertility index (If) and total selection intensity index (I) were analyzed among the studied population. The Crows total index (It) value was found to be 0.7246. The mortality (Im) component was found to be 0.5385 while the fertility (If) component was found to be 0.1846. The contribution of fertility component is greater than that of mortality component among the present studied population using Crows index. According to Johnston and Kesinger the total index (It) was found to be 0.8367. Where, fertility component was found to be 0.0885, Prenatal mortality component (Ime) and Postnatal mortality component (Ime/Pb) where observed to be 0.1356 and 0.1540. Therefore, it has been clear from the result that prenatal mortality contributes higher than that of postnatal mortality for selection. i.e., Johnston and Kesingers Index (0.8367) contributes higher for the opportunity of natural selection than Crows Index (0.7246).

scholarly journals Dynamics of indexes of reproduction and selection in three generations of the urbanized population

2020 ◽  
Vol 26 ◽  
pp. 61-66
Author(s):  
N. O. Kozak ◽  
L. A. Atramentova
Keyword(s):  
First Generation ◽  
Selection Index ◽  
Reproductive Technologies ◽  
Differential Mortality ◽  
Third Generation ◽  
Differential Fertility ◽  
Quantitative Characteristics ◽  
History Of ◽  
Successive Generations ◽  
Total Selection

Aim. Due to the fact that women's reproductive behavior has been changing with the development of civilization, from natural uncontrolled fertility in the early stages of human development to reproductive technologies in our time, the aim of this work was to study the direction and intensity of natural selection index and changes of the quantitative characteristics of reproduction in women residents of Kharkiv in three successive generations. Methods. Material was collected in 1990 and 2017. The obstetric and gynecological history of the inhabitants of Kharkiv was studied. The first generation included 589 women who were born in 1900–1925, 244 women born in the period 1928–1955, made up the second generation, 288 women who were born in 1956–1979, were assigned to third generation. Results. The total selection index is reduced from 0.56 in the first generation to 0.29 and 0.28 in the second and third generations, respectively. Over the eighty-year period, the differential fertility rate has decreased. The percentage of women with pathological pregnancies increased from 4.9 in the first generation, to 22.5 in the second and 18.4 in the third generation. Conclusions. The total selection index in the Kharkiv population into three successive generations has decreased by half: from 0.56 to 0.28, the index of differential mortality has decreased by almost four times. Keywords: reproductive characteristics, Kharkov population, Crow's index, selection, generations.

scholarly journals EFFECTS OF POPULATION SIZE AND SELECTION INTENSITY ON SHORT-TERM RESPONSE TO SELECTION FOR POSTWEANING GAIN IN MICE

Genetics ◽  
1973 ◽  
Vol 73 (3) ◽  
pp. 513-530
Author(s):  
J P Hanrahan ◽  
E J Eisen ◽  
J E Legates
Keyword(s):  
Population Size ◽  
Selection Response ◽  
Selection Intensity ◽  
Realized Heritability ◽  
Family Selection ◽  
Effective Population ◽  
Population Sizes ◽  
Selection For ◽  
Selection Intensities ◽  
Term Response

ABSTRACT The effects of population size and selection intensity on the mean response was examined after 14 generations of within full-sib family selection for postweaning gain in mice. Population sizes of 1, 2, 4, 8 and 16 pair matings were each evaluated at selection intensities of 100% (control), 50% and 25% in a replicated experiment. Selection response per generation increased as selection intensity increased. Selection response and realized heritability tended to increase with increasing population size. Replicate variability in realized heritability was large at population sizes of 1, 2 and 4 pairs. Genetic drift was implicated as the primary factor causing the reduced response and lowered repeatability at the smaller population sizes. Lines with intended effective population sizes of 62 yielded larger selection responses per unit selection differential than lines with effective population sizes of 30 or less.

scholarly journals EFFECTS OF POPULATION SIZE AND SELECTION INTENSITY ON RESPONSES TO DISRUPTIVE SELECTION IN DROSOPHILA MELANOGASTER

Genetics ◽  
1974 ◽  
Vol 78 (2) ◽  
pp. 715-735
Author(s):  
J S F Barker ◽  
L J E Karlsson
Keyword(s):  
Assortative Mating ◽  
Random Mating ◽  
Female Parent ◽  
Disruptive Selection ◽  
Lethal Gene ◽  
Selection Intensity ◽  
Bristle Number ◽  
Isolation Index ◽  
Selection Intensities ◽  
High Selection

ABSTRACT Disruptive selection for sternopleural bristle number with opportunity for random mating was done in the four treatment combinations of two population sizes (40 pairs and 8 pairs of selected parents) and two selection intensities (1 in 40 and 1 in 2). In each generation, matings among selected parents were observed in a mating chamber, and progeny collected separately from each female parent. In the high number, high selection intensity treatment, divergence between the high and low parts ceased about generation 11. The isolation index increased rapidly to generation 3, but then fluctuated to termination of the population at generation 17. The overall isolation index was significant, indicating a real tendency to assortative mating. The failure of the isolation index to increase after generation 3 was attributed to lower average mating fitness of high males (due to inbreeding) and reduced receptivity of low females (due to a homozygous lethal gene with a large effect on sternopleural bristle number in heterozygotes). In the two low number treatments, isolation indices fluctuated from generation to generation with no obvious trends, and none of the overall isolation indices were significantly different from zero. The high number, low selection intensity treatment showed very little divergence, and one of the replicates showed, in contrast with expectation and the high number, high selection intensity treatment, a significant tendency to disassortative mating. Intense disruptive selection may lead to assortative mating.

scholarly journals Optimum selection intensities in artificial selection programmes: an experimental evaluation

1977 ◽  
Vol 30 (2) ◽  
pp. 115-119 ◽  
Author(s):  
R. Frankham
Keyword(s):  
Experimental Evaluation ◽  
Selection Intensity ◽  
Effective Population ◽  
Term Selection ◽  
Optimum Selection ◽  
Selection For ◽  
Selection Intensities ◽  
Selection Of ◽  
Better Than

SUMMARYAn experimental evaluation of Robertson's (1970) theory concerning optimum intensities of selection for selection of varying durations has been carried out using published results from a long term selection study in Drosophila. Agreement of predicted rankings of treatments with expectations was excellent for low values of t/T (generations/total number scored) but poor for larger values of t/T. This was due to the 20% selection intensity treatments responding worse than expected and the 40% treatments relatively better than expected. Several possible reasons for the discrepancies exist but the most likely explanation is considered to be the greater reduction in effective population size due to selection in treatments with more intense selection.

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