Related Concept Videos
01:07Speciation Rates
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Overview
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02:27Background and Environment Affect Phenotype
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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...
6.5K
01:38Limits to Natural Selection
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Organisms that are well-adapted to their environment are more likely to survive and reproduce. However, natural selection does not lead to perfectly adapted organisms. Several factors constrain natural selection.
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01:46Types of Selection
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Natural selection influences the frequencies of particular alleles and phenotypes within populations in several different ways. Primarily, natural selection can be directional, stabilizing, or disruptive. Directional selection favors one extreme trait and shifts the population towards that phenotype while selecting against individuals displaying alternate traits. Stabilizing selection favors an intermediate trait with a narrow range of variation. Deviation from the optimal phenotype towards an...
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02:32Position-effect Variegation
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In 1928, a German botanist Emil Heitz observed the moss nuclei with a DNA binding dye. He observed that while some chromatin regions decondense and spread out in the interphase nucleus, others do not. He termed them euchromatin and heterochromatin, respectively. He proposed that the heterochromatin regions reflect a functionally inactive state of the genome. It was later confirmed that heterochromatin is transcriptionally repressed, and euchromatin is transcriptionally active chromatin.
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01:21Frequency-dependent Selection
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When the fitness of a trait is influenced by how common it is (i.e., its frequency) relative to different traits within a population, this is referred to as frequency-dependent selection. Frequency-dependent selection may occur between species or within a single species. This type of selection can either be positive—with more common phenotypes having higher fitness—or negative, with rarer phenotypes conferring increased fitness.
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The loci of insect phenotypic evolution.
1Université Paris Cité, CNRS, Institut Jacques Monod, 75013 Paris, France.
Current Opinion in Insect Science
|October 20, 2023
Summary
Genetic mutations drive insect evolution and adaptation. This study analyzes over 600 mutations, revealing patterns in insect genetic variation and highlighting key evolutionary mechanisms like standing variation and introgression.
Area of Science:
- Ecology
- Genetics
- Evolutionary Biology
Background:
- Insects play crucial roles in terrestrial ecosystems, including pollination, pestilence, disease transmission, and as a food source.
- Understanding the genetic basis of insect phenotypic variation is essential for ecology, agriculture, and public health.
Purpose of the Study:
- To explore the current knowledge on genes and mutations contributing to natural phenotypic variation in insects.
- To analyze trends in data collection and identify patterns in genetic variation research.
Main Methods:
- Utilized Gephebase, a curated database of genetic variants linked to natural and domesticated trait variation.
- Analyzed over 600 mutations to assess species and trait distribution, and experimental approaches over time.
Main Results:
- Data on insect genetic variation are concentrated in specific species and traits.
- The distribution of coding and cis-regulatory changes varies significantly across traits, experimental methods, and gene loci.
- Recent research emphasizes the roles of standing variation, recurrent mutations in hotspot genes, recombination, inversions, and introgression.
Conclusions:
- Current research on insect genetic variation is unevenly distributed, necessitating broader investigation.
- Evolutionary mechanisms such as standing variation, recombination, and introgression are critical drivers of insect adaptation and diversity.