scholarly journals Genetic variation for an aphid wing polyphenism is genetically linked to a naturally occurring wing polymorphism

2005 ◽  
Vol 272 (1563) ◽  
pp. 657-664 ◽  
Author(s):  
Christian Braendle ◽  
Ilvy Friebe ◽  
Marina C Caillaud ◽  
David L Stern
Keyword(s):  
Genetic Variation ◽  
Wing Polymorphism ◽  
Naturally Occurring

scholarly journals Correction for Braendle et al. , Genetic variation for an aphid wing polyphenism is genetically linked to a naturally occurring wing polymorphism

2005 ◽  
Vol 272 (1581) ◽  
pp. 2659-2659 ◽  
Author(s):  
Christian Braendle ◽  
Ilvy Friebe ◽  
Marina C. Caillaud ◽  
David L. Stern
Keyword(s):  
Genetic Variation ◽  
Wing Polymorphism ◽  
Print Version ◽  
Related Article ◽  
Correct Figure ◽  
Link Type ◽  
Naturally Occurring ◽  
Article Type

Correction for ‘Genetic variation for an aphid wing polyphenism is genetically linked to a naturally occurring wing polymorphism’ by Christian Braendle, Ilvy Friebe, Marina C. Caillaud and David L. Stern (Proc. R. Soc. B 272 , 657–664. (doi: 10.1098/rspb.2004.2995 )). Figure 2 in the print version of this paper is incorrect; the correct figure is as follows.

Markers, maps and the detection of trait loci

1996 ◽  
Vol 1996 ◽  
pp. 50-50
Author(s):  
C.S. Haley
Keyword(s):  
Genetic Variation ◽  
Quantitative Trait Loci ◽  
Genetic Markers ◽  
Quantitative Trait ◽  
Coat Colour ◽  
Combined Effects ◽  
Potential Interest ◽  
Naturally Occurring ◽  
Trait Loci ◽  
Modern Breeding

Naturally occurring genetic variation is the basis for differences in performance and appearance between and within different breeds and lines of livestock. In a few instances (e.g. coat colour, polling) the genes (or loci) which control the variation between animals and breeds have a large enough effect to be individually recognisable. For many traits, however, the combined effects of many different genes act together to control quantitative differences between breeds and individuals within breeds (hence such genes are often referred to as quantitative trait loci or QTLs). Thus the dramatic successes of modern breeding result from generations of selection which has produced accumulated changes at a number of different loci. The genome contains up to 100,000 different genes and identifying those which contribute to variation in traits of interest is a difficult task. One first step is to identify regions of the genome containing loci of potential interest through their linkage to genetic markers.

scholarly journals Genetic Variation in Adaptability and Pleiotropy in Budding Yeast

2017 ◽  
Author(s):  
Elizabeth R. Jerison ◽  
Sergey Kryazhimskiy ◽  
James Mitchell ◽  
Joshua S. Bloom ◽  
Leonid Kruglyak ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Complex Traits ◽  
Genetic Basis ◽  
Average Rate ◽  
Environmental Condition ◽  
Future Evolution ◽  
Naturally Occurring ◽  
Yeast Strains ◽  
Offspring Genotype ◽  
Specific Environmental Condition

AbstractEvolution can favor organisms that are more adaptable, provided that genetic variation in adaptability exists. Here, we quantify this variation among 230 offspring of a cross between diverged yeast strains. We measure the adaptability of each offspring genotype, defined as its average rate of adaptation in a specific environmental condition, and analyze the heritability, predictability, and genetic basis of this trait. We find that initial genotype strongly affects adaptability and can alter the genetic basis of future evolution. Initial genotype also affects the pleiotropic consequences of adaptation for fitness in a different environment. This genetic variation in adaptability and pleiotropy is largely determined by initial fitness, according to a rule of declining adaptability with increasing initial fitness, but several individual QTLs also have a significant idiosyncratic role. Our results demonstrate that both adaptability and pleiotropy are complex traits, with extensive heritable differences arising from naturally occurring variation.

COMPONENTS OF SELECTION IN X CHROMOSOME LINES OF DROSOPHILA MELANOGASTER: SEX RATIO MODIFICATION BY MEIOTIC DRIVE AND VIABILITY SELECTION

Genetics ◽  
1984 ◽  
Vol 108 (4) ◽  
pp. 941-952
Author(s):  
James W Curtsinger
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Variation ◽  
Maximum Likelihood ◽  
Sex Ratio ◽  
Genetic Background ◽  
Likelihood Estimation ◽  
Meiotic Drive ◽  
Mendelian Segregation ◽  
Viability Selection ◽  
Naturally Occurring

ABSTRACT Selection coefficients and segregation parameters have been estimated in 18 randomly chosen lines carrying wild Χ chromosomes on the cn bw genetic background. Each line was studied in replicated crosses of four types, with approximately 100 replications per line per cross. Crosses in which male Χ chromosomes differed exhibited significant sex ratio heterogeneity. Maximum likelihood estimation of segregation parameters revealed two lines in which the proportion of Χ-bearing gametes produced by males was significantly different from Mendelian expectations. These observations suggest that segregation distortion is a common feature of naturally occurring genetic variation. Non-Mendelian segregation has important evolutionary implications.

scholarly journals Host Genotype and Precipitation Influence of Fungal Endophyte Symbiosis and Mycotoxin Abundance in a Locoweed

2019 ◽  
Vol 20 (21) ◽  
pp. 5285
Author(s):  
Wei He ◽  
Linwei Guo ◽  
Lei Wang ◽  
Qianqian Zhao ◽  
Lizhu Guo ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Geographical Location ◽  
Population Level ◽  
Fungal Endophyte ◽  
Host Population ◽  
Host Genotype ◽  
Symbiotic Interactions ◽  
Naturally Occurring ◽  
Endophyte Infection ◽  
Host Genetic

Many plant endophytes produce mycotoxins, but how host genetic variation influences endophyte colonization and mycotoxin production under natural conditions is poorly understood. This interaction has not been fully considered in many previous studies which used controlled experiments with agronomic or model plant species. Here, we investigated this interaction in a naturally occurring forb (a locoweed species) Oxytropis ochrocephala, its symbiotic endophyte Alternaria oxytropis, and the mycotoxin swainsonine. Host genetic variation was characterized by microsatellite markers. Endophyte infection rate and swainsonine levels were determined by PCR and HPLC, respectively. Genetic markers defined two distinct host populations and revealed that host genetics were significantly correlated with geographical location, elevation, and precipitation. As the host diverged, symbiotic interactions were reduced or failed to produce detectable swainsonine in one host population. Host genotype and precipitation had a significant impact in shaping swainsonine production at the population level. This study highlights the effect of host genotype in influencing this interaction in locoweeds.

scholarly journals Genetic Variation in Rates of Nondisjunction: Association of Two Naturally Occurring Polymorphisms in the Chromokinesin nod With Increased Rates of Nondisjunction in Drosophila melanogaster

Genetics ◽  
1999 ◽  
Vol 152 (4) ◽  
pp. 1605-1614 ◽  
Author(s):  
Michael E Zwick ◽  
Jennifer L Salstrom ◽  
Charles H Langley
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Variation ◽  
Chromosome Segregation ◽  
Natural Populations ◽  
Intermediate Frequency ◽  
Female Meiosis ◽  
X Chromosomes ◽  
Naturally Occurring ◽  
High Level ◽  
Female Specific

Abstract Genetic variation in nondisjunction frequency among X chromosomes from two Drosophila melanogaster natural populations is examined in a sensitized assay. A high level of genetic variation is observed (a range of 0.006-0.241). Two naturally occurring variants at the nod locus, a chromokinesin required for proper achiasmate chromosome segregation, are significantly associated with an increased frequency of nondisjunction. Both of these polymorphisms are found at intermediate frequency in widely distributed natural populations. To account for these observations, we propose a general model incorporating unique opportunities for meiotic drive during female meiosis. The oötid competition model can account for both high mean rates of female-specific nondisjunction in Drosophila and humans as well as the standing genetic variation in this critical fitness character in natural populations.

scholarly journals Genetic variation in adaptability and pleiotropy in budding yeast

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Elizabeth R Jerison ◽  
Sergey Kryazhimskiy ◽  
James Kameron Mitchell ◽  
Joshua S Bloom ◽  
Leonid Kruglyak ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Complex Traits ◽  
Genetic Basis ◽  
Average Rate ◽  
Environmental Condition ◽  
Future Evolution ◽  
Naturally Occurring ◽  
Yeast Strains ◽  
Offspring Genotype ◽  
Specific Environmental Condition

Evolution can favor organisms that are more adaptable, provided that genetic variation in adaptability exists. Here, we quantify this variation among 230 offspring of a cross between diverged yeast strains. We measure the adaptability of each offspring genotype, defined as its average rate of adaptation in a specific environmental condition, and analyze the heritability, predictability, and genetic basis of this trait. We find that initial genotype strongly affects adaptability and can alter the genetic basis of future evolution. Initial genotype also affects the pleiotropic consequences of adaptation for fitness in a different environment. This genetic variation in adaptability and pleiotropy is largely determined by initial fitness, according to a rule of declining adaptability with increasing initial fitness, but several individual QTLs also have a significant idiosyncratic role. Our results demonstrate that both adaptability and pleiotropy are complex traits, with extensive heritable differences arising from naturally occurring variation.

The adaptive function of sexual reproduction: resampling the pool of genotypic possibilities.

2021 ◽  
Author(s):  
Donal Hickey ◽  
Brian Golding
Keyword(s):  
Genetic Variation ◽  
Natural Selection ◽  
Sexual Reproduction ◽  
Finite Population ◽  
Adaptive Function ◽  
Asexual Population ◽  
Sexual Population ◽  
Naturally Occurring ◽  
The Cost ◽  
The Universe

Abstract BackgroundNatural populations harbor significant levels of genetic variability. Because of this standing genetic variation, the number of possible genotypic combinations is many orders of magnitude greater than the population size. This means that any given population contains only a tiny fraction of all possible genotypic combinations.ResultsWe show that recombination allows a finite population to resample the genotype pool, i.e., the universe of all possible genotypic combinations. Recombination, in combination with natural selection, enables an evolving sexual population to replace existing genotypes with new, higher-fitness genotypic combinations that did not previously exist in the population. Gradually the selected sexual population approaches a state where the optimum genotype is produced by recombination and where it rises to fixation. In contrast to this, an asexual population is limited to selection among existing lower fitness genotypes.ConclusionsThe significance of the result is two-fold. First, it provides an explanation for the ubiquity of sexual reproduction in evolving populations. Secondly, it shows that recombination serves to remove concerns about the cost of natural selection acting on the naturally occurring standing genetic variation. This means that classic population genetics theory is applicable to ecological studies of natural selection acting on standing genetic variation.

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