Talk:Effective population size
Discussion page of Effective population size
More actions
Talk
Discussion for: Effective population size • View • Links • Related changes
Use this page for verification notes, disputes, and action items. Keep narrative content on the article.
Page scope
Effective population size covers the effective population size: its definition by the idealised population, its relation to the census size, what lowers or raises it in a population grown for seed (the numbers of each sex, unequal shares of offspring, changes in size between generations, overlapping generations and linked selection), its estimation from demographic and genetic data, the estimate of the past effective size of cannabis, and its use in conservation, including the plant numbers set for regrowing cannabis seed collections. The random change in allele frequency that effective size governs belongs to Genetic drift; the choice of parents by growers to Mass selection; the balance of drift against selection to Natural selection.
Data verification
Record source conflicts, dating problems and sources not used here. Keep narrative content on the article.
Discussion
Sources
- Felsenstein, Theoretical Evolutionary Genetics (text of December 2019), pp. 251–252, 263, 266–275, 289–290 and 326–328: the idealised population; inbreeding and variance effective numbers and Crow's distinction (1954); Wright (1931, 1938); separate sexes (formula and table of sex ratios); the harmonic mean over changing sizes; variance in offspring number and fertility; overlapping generations and hitchhiking; 4Neu; the 4Nes criterion.
- Davinack, Molecular Ecology & Evolution: An Introduction (2024), pp. 110–112 and 165–166: census and effective size; the causes of a low effective size; its role in conservation.
- Gargiulo and colleagues (2024), Evolutionary Applications 17: e13691: the effective size above 500 as an indicator of the Kunming-Montreal Global Biodiversity Framework; the rule of thumb of a tenth of the census size; demographic and genetic estimation, the linkage disequilibrium and temporal methods and their biases; the difficulties plants raise; sample sizes in wild apricot.
- Ren and colleagues (2021), Science Advances 7: eabg2286: the history of effective size in four groups of cannabis inferred from whole genomes, the assumptions used to convert it to years and the best-fitting model of domestication.
- Lemeshev, Rumyantseva and Clarke (1994), Journal of the International Hemp Association 1: 3–5: the Vavilov Institute collection, mostly wild landraces and fibre hemp varieties, and the need to regrow it every five years.
- Lemeshev, Rumyantseva and Clarke (1995), Journal of the International Hemp Association 2: 10–13: the 1,000- and 2,000-plant figures for monoecious and dioecious accessions; isolation by distance and by ripening time; the results for 1993 and 1994.
- Clarke (1998), Journal of the International Hemp Association 5: 75–79: the five-year results of the programme and the lowering of its seed standard.
- Welling and colleagues (2016), Frontiers in Plant Science 7: 1113: pollen-secure facilities as a standard alternative to outdoor regeneration and the limit their space sets.
- Cramer (January 2024), "The USDA-ARS hemp germplasm repository", Cornell Hemp: the 581 accessions at Geneva, New York, regrown indoors; the curator's account of growing as many plants as possible, and of growth chambers and "hemp huts".
Terms
- Effective population size and effective population number are the same quantity. Felsenstein uses both; Wright's term was effective population number.
- The census size (Nc) is the number of individuals counted; Gargiulo and colleagues use it for adults.
- Inbreeding effective size and variance effective size come from the two comparisons with the idealised population. The formulas in Felsenstein's chapter give inbreeding effective sizes.
- Regrowing, regeneration and reproduction all name the growing of a stored seed accession to obtain fresh seed.
Source discrepancies
- How much of a gene pool 1,000 plants keep. The Vavilov Institute report on 1993 expected 1,000 plants to keep 99 per cent of an accession's gene pool. The report on 1994 gave 99 per cent for monoecious and 95 per cent for dioecious varieties and 2,000 plants for 99 per cent in a dioecious accession. The figures are the project's own; it attributes the basis to Crossa and colleagues (1993), Theoretical and Applied Genetics 86: 673–678. The five-year report of 1998 repeats the 99 per cent figure without the distinction.
- The seed standard. The project's minimum of 200 g of seed for each regrowing was lowered to 120 g after long-term storage was installed at St Petersburg (Clarke 1998).
Images reserved in the article
One image has a place in the article but is not yet uploaded:
File:Cannabis-effective-size-sex-ratio.jpg(lead image, in the series box), a graph to be drawn: a horizontal axis "Female plants in a population of 100" from 0 to 100 and a vertical axis "Effective population size" from 0 to 100. One curve, symmetric about 50, through points at 4.5 (1 female), 19.5 (5), 36.5 (10), 75.5 (25), 100.5 (50) and the mirror values for 75, 90, 95 and 99 females. Two point labels: "5 females, 95 males: about 20" and "50 of each: about 100". No crop names or measured data.