Related Experiment Video
Updated: May 24, 2026
10:17
An Allele-specific Gene Expression Assay to Test the Functional Basis of Genetic Associations
Published on: November 3, 2010
Genetic variation underlying the expression of a polyphenism.
Bruno A Buzatto1, L W Simmons, J L Tomkins
1Centre for Evolutionary Biology, School of Animal Biology (M092), The University of Western Australia, Crawley, WA, Australia. bruno.buzatto@gmail.com
Journal of Evolutionary Biology
|February 24, 2012
Summary
Genetic variation exists for conditional traits in mites, where environmental cues determine male phenotypes. This study explored genetic variation for switchpoints in male mite dimorphism, revealing differences among inbred lines.
Area of Science:
- Evolutionary biology
- Quantitative genetics
Background:
- Polyphenic traits are common and influenced by environmental factors.
- The environmentally cued threshold (ET) model describes phenotypic switches as polygenic traits.
- Empirical studies on genetic variation for these switchpoints are limited.
Purpose of the Study:
- To investigate the genetic variation for switchpoints in polyphenic traits.
- To test the predictions of the ET model regarding genetic variation for switchpoints.
- To explore the genetic architecture of conditional strategies in Rhizoglyphus echinopus.
Main Methods:
- Utilized inbred lines of the mite Rhizoglyphus echinopus.
- Examined male dimorphism (fighters vs. scramblers) as a polyphenic trait.
- Assessed the conditionality of male dimorphism across different inbred lines.
Main Results:
- Significant genetic variation for switchpoints was detected among inbred lines.
- The conditionality of male dimorphism varied significantly between inbred lines.
- Results support the ET model's prediction of genetic variation for switchpoints.
- Evidence suggests a mix of canalized and conditional strategists in the studied mite population.
Conclusions:
- The study provides empirical evidence for genetic variation in the switchpoints of polyphenic traits.
- Major genes may influence both morph expression canalization and conditional expression extent.
- These findings have implications for understanding the genetic basis of threshold traits in other species.
Related Concept Videos
02:27Background and Environment Affect Phenotype
Although the genetic makeup of an organism plays a major role in determining the phenotype, there are also several environmental factors, such as temperature, oxygen availability, presence of mutagens, that can alter an organism’s phenotype.
An example of how genetic background affects phenotype can be seen in horses. The Extension gene in horses is responsible for their coat color. A wild-type gene (EE) produces black pigment in the coat, while a mutant gene (ee) produces red pigment. A...
An example of how genetic background affects phenotype can be seen in horses. The Extension gene in horses is responsible for their coat color. A wild-type gene (EE) produces black pigment in the coat, while a mutant gene (ee) produces red pigment. A...
01:25Genetic Variation
Genetic variation is the diversity in DNA sequences found among individuals of the same species. This diversity is crucial for a species' survival because it helps organisms adapt to environmental changes. Genetic variation begins with fertilization, where an egg and sperm cell merge. Each of these cells carries 23 chromosomes, up to 46 in the fertilized egg. Chromosomes are long DNA strands that contain genes, the basic units of heredity.
Genes exist in different versions called alleles, which...
Genes exist in different versions called alleles, which...
01:39Epistasis
In addition to multiple alleles at the same locus influencing traits, numerous genes or alleles at different locations may interact and influence phenotypes in a phenomenon called epistasis. For example, rabbit fur can be black or brown depending on whether the animal is homozygous dominant or heterozygous at a TYRP1 locus. However, if the rabbit is also homozygous recessive at a locus on the tyrosinase gene (TYR), it will have an unshaded coat that appears white, regardless of its TYRP1...
01:18Polygenic Traits
When more than one gene is responsible for a given phenotype, the trait is considered polygenic. Human height is a polygenic trait. Studies have uncovered hundreds of loci that influence height, and there are believed to be many more. Due to the high number of genes involved, as well as environmental and nutritional factors, height varies significantly within a given population. The distribution of height forms a bell-shaped curve, with relatively few individuals in the population at the...
01:18Polygenic Traits
When more than one gene is responsible for a given phenotype, the trait is considered polygenic. Human height is a polygenic trait. Studies have uncovered hundreds of loci that influence height, and there are believed to be many more. Due to the high number of genes involved, as well as environmental and nutritional factors, height varies significantly within a given population. The distribution of height forms a bell-shaped curve, with relatively few individuals in the population at the...
01:09Epistasis Analysis
Although Mendel chose seven unrelated traits in peas to study gene segregation, most traits involve multiple gene interactions that create a spectrum of phenotypes. When the interaction of various genes or alleles at different locations influences a phenotype, this is called epistasis. Epistasis often involves one gene masking or interfering with the expression of another (antagonistic epistasis). Epistasis often occurs when different genes are part of the same biochemical pathway. The...