Related Experiment Video
Updated: May 18, 2026
03:50
Effectiveness of the Air Stripping in Two Salmonid Fish, Rainbow Trout (Oncorhynchus Mykiss) and Brown Trout (Salmo Trutta Morpha fario)
Published on: September 16, 2018
Balancing selection on MHC class I in wild brown trout Salmo trutta
B O'Farrell1, C Dennis, J A Benzie
1Environmental Research Institute, University College Cork, Cork, Ireland. b.ofarrell@ucc.ie
Journal of Fish Biology
|September 11, 2012
Summary
Balancing selection maintains variation at the Major Histocompatibility Complex (MHC) in brown trout populations. This genetic diversity persists even in isolated groups, unlike neutral markers.
Area of Science:
- Evolutionary genetics
- Population genetics
- Immunogenetics
Background:
- The Major Histocompatibility Complex (MHC) plays a crucial role in immune response and is known to be highly variable.
- Balancing selection is a proposed evolutionary mechanism maintaining genetic diversity at MHC loci.
- Understanding MHC evolution in wild populations provides insights into host-pathogen dynamics and adaptation.
Purpose of the Study:
- To investigate evidence for balancing selection acting on MHC variation in wild brown trout (Salmo trutta).
- To compare patterns of genetic variation at an MHC-linked locus with neutral markers in isolated and connected populations.
- To elucidate the population structure of brown trout across different catchments.
Main Methods:
- Microsatellite genotyping was used to analyze variation at an MHC class I-linked locus (mhc1) and neutral markers.
- Genetic differentiation (Fst) was calculated between populations for both MHC and neutral loci.
- Population structure was inferred using genetic data.
Main Results:
- Variation at the mhc1 locus was retained in small, isolated brown trout populations where neutral markers lost variation.
- Brown trout populations showed less genetic differentiation at mhc1 compared to neutral markers across catchments.
- Distinct population structure patterns were observed for MHC and neutral markers.
Conclusions:
- The findings provide strong evidence for balancing selection maintaining MHC diversity in wild brown trout.
- MHC variation is subject to different evolutionary forces than neutral genetic variation in these populations.
- The study highlights the importance of MHC genetic diversity for the adaptation and resilience of wild fish populations.
More Related Videos
11:17Stability and Structure of Bat Major Histocompatibility Complex Class I with Heterologous β2-Microglobulin
Published on: March 10, 2021
06:41Assays to Detect UV-reflecting Structures and Determine their Importance in Mate Preference using the Sailfin Molly Poecilia latipinna
Published on: September 14, 2016
Related Concept Videos
01:46Types of Selection
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...
01:24Testing a Claim about Population Proportion
A complete procedure for testing a claim about a population proportion is provided here.
There are two methods of testing a claim about a population proportion: (1) Using the sample proportion from the data where a binomial distribution is approximated to the normal distribution and (2) Using the binomial probabilities calculated from the data.
The first method uses normal distribution as an approximation to the binomial distribution. The requirements are as follows: sample size is large...
There are two methods of testing a claim about a population proportion: (1) Using the sample proportion from the data where a binomial distribution is approximated to the normal distribution and (2) Using the binomial probabilities calculated from the data.
The first method uses normal distribution as an approximation to the binomial distribution. The requirements are as follows: sample size is large...
01:21Frequency-dependent Selection
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.
02:32Osmoregulation in Fishes
When cells are placed in a hypotonic (low-salt) fluid, they can swell and burst. Meanwhile, cells in a hypertonic solution—with a higher salt concentration—can shrivel and die. How do fish cells avoid these gruesome fates in hypotonic freshwater or hypertonic seawater environments?
01:49Hardy-Weinberg Principle
Diploid organisms have two alleles of each gene, one from each parent, in their somatic cells. Therefore, each individual contributes two alleles to the gene pool of the population. The gene pool of a population is the sum of every allele of all genes within that population and has some degree of variation. Genetic variation is typically expressed as a relative frequency, which is the percentage of the total population that has a given allele, genotype or phenotype.
01:06Fixed Action Patterns
A fixed action pattern (FAP) is a specific, hard-wired sequence of behaviors that occurs in response to an external stimulus, called a sign stimulus. The behavior is “fixed” because it is essentially unchangeable—proceeding similarly across individuals of a species every time it occurs.