Genetic Structure of Populations. III. Natural Selection and Concealed Genetic Variability in a Natural Population of Drosophila melanogaster

Evolution ◽  
1964 ◽  
Vol 18 (3) ◽  
pp. 384 ◽  
Author(s):  
H. T. Band
Keyword(s):  
Drosophila Melanogaster ◽  
Natural Selection ◽  
Genetic Structure ◽  
Genetic Variability ◽  
Natural Population ◽  
Genetic Structure Of Populations

scholarly journals GENETIC LOAD IN NATURAL POPULATIONS: IS IT COMPATIBLE WITH THE HYPOTHESIS THAT MANY POLYMORPHISMS ARE MAINTAINED BY NATURAL SELECTION?

Genetics ◽  
1974 ◽  
Vol 77 (3) ◽  
pp. 569-589
Author(s):  
Martin L Tracey ◽  
Francisco J Ayala
Keyword(s):  
Drosophila Melanogaster ◽  
Natural Selection ◽  
Natural Population ◽  
Natural Populations ◽  
Genetic Load ◽  
Structural Genes ◽  
Invertebrate Species ◽  
Average Proportion ◽  
Mean Fitness ◽  
The Mean

ABSTRACT Recent studies of genetically controlled enzyme variation lead to an estimation that at least 30 to 60% of the structural genes are polymorphic in natural populations of many vertebrate and invertebrate species. Some authors have argued that a substantial proportion of these polymorphisms cannot be maintained by natural selection because this would result in an unbearable genetic load. If many polymorphisms are maintained by heterotic natural selection, individuals with much greater than average proportion of homozygous loci should have very low fitness. We have measured in Drosophila melanogaster the fitness of flies homozygous for a complete chromosome relative to normal wild flies. A total of 37 chromosomes from a natural population have been tested using 92 experimental populations. The mean fitness of homozygous flies is 0.12 for second chromosomes, and 0.13 for third chromosomes. These estimates are compatible with the hypothesis that many (more than one thousand) loci are maintained by heterotic selection in natural populations of D. melanogaster.

scholarly journals genetic variability of sukachev's larch (larix sukaczewii djil.) in geographical cultures under Voronezh

2018 ◽  
Vol 8 (1) ◽  
pp. 37-44
Author(s):  
Евгений Кулаков ◽  
Evgeniy Kulakov ◽  
Владимир Сиволапов ◽  
Vladimir Sivolapov ◽  
Елена Воробьева ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Genetic Variability ◽  
Forest Tree ◽  
Microsatellite Analysis ◽  
Accurate Information ◽  
Forest Plantations ◽  
Allelic Variants ◽  
Genetic Structure Of Populations ◽  
Electrophoretic Spectra ◽  
Nuclear Microsatellite

Information on the genetic structure of populations of forest tree plants is the basis for assessing the genetic po-tential of the species. These studies are particularly relevant for economically valuable species and species occupying extensive areas, like larch. Accurate information about the genetic structure of populations, the level of their genetic variability, the nature of its distribution within the range allows us to designate measures aimed at preserving the genet-ic resources of the species for the use in the country's economy and reproduction. During the analysis of electrophoretic spectra of the products of amplification of six nuclear microsatellite loci 42 allelic variants have been identified. An estimation of the genetic polymorphism of the population structure of forest plantations of Sukachev’s larch from the seeds of the Sverdlovsk region by microsatellite analysis for 6 pairs of pri-mers is given.

scholarly journals The Genetic Structure of the Raleigh Natural Population of Drosophila melanogaster Revisited

Genetics ◽  
2000 ◽  
Vol 154 (2) ◽  
pp. 679-685
Author(s):  
Shinichi Kusakabe ◽  
Yumi Yamaguchi ◽  
Hiroshi Baba ◽  
Terumi Mukai
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Structure ◽  
Natural Population ◽  
Genetic Background ◽  
Effective Size ◽  
Laboratory Line

Abstract The Raleigh natural population of Drosophila melanogaster was reanalyzed with special attention to possible dysgenic effects during the extraction of chromosomes. About 600 second chromosomes were extracted from the Raleigh natural population, half in the cytoplasm of wild-caught females (native genetic background) and half in the cytoplasm of the laboratory line, C160(In(2LR)SM1, Cy/In(2LR)bwV1) (foreign genetic background). We could not find significant differences between the two extraction schemes in the frequency of lethal second chromosomes (Q = 0.252 for the lines with the negative genetic background vs. 0.231 for the lines with the foreign genetic background) or in the homozygous detrimental (D) and lethal (L) loads (D = 0.210 vs. 0.251; L = 0.287 vs. 0.264). The effective size of the population was estimated to be ~19,000, based on the allelism rate of lethal-bearing chromosomes. The homozygous load markedly decreased in the 15 years since a previous study of the same population.

scholarly journals The genetic structure of populations of orchids and its evolutionary importance: understanding processes from patterns

Lankesteriana ◽  
2016 ◽  
Vol 3 (2) ◽  
Author(s):  
Raymond L. Tremblay
Keyword(s):  
Gene Flow ◽  
Natural Selection ◽  
Genetic Structure ◽  
Population Size ◽  
Effective Population Size ◽  
Genetic Drift ◽  
Mating Systems ◽  
Mutation Rates ◽  
Effective Population ◽  
Genetic Structure Of Populations

<div class="page" title="Page 1"><div class="layoutArea"><div class="column"><p><span>Evolution through either natural selection or genetic drift is dependent on variation at the genetic and mor- phological levels. Processes that influence the genetic structure of populations include mating systems, effective population size, mutation rates and gene flow among populations. </span></p></div></div></div>

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