Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Mutation, Gene Flow, and Genetic Drift01:09

Mutation, Gene Flow, and Genetic Drift

58.4K
In a population that is not at Hardy-Weinberg equilibrium, the frequency of alleles changes over time. Therefore, any deviations from the five conditions of Hardy-Weinberg equilibrium can alter the genetic variation of a given population. Conditions that change the genetic variability of a population include mutations, natural selection, non-random mating, gene flow, and genetic drift (small population size).
58.4K
Conservation of Small Populations02:04

Conservation of Small Populations

13.2K
Small population sizes put a species at extreme risk of extinction due to a lack of variation, and a consequent decrease in adaptability. This weakens the chances of survival under pressures such as climate change, competition from other species, or new diseases. Large populations are more likely to survive pressures such as these, as such populations are more likely to harbor individuals that have genetic variants that are adaptive under new stresses. Small populations are much less...
13.2K
Genetics of Speciation02:16

Genetics of Speciation

19.3K
Speciation is the evolutionary process resulting in the formation of new, distinct species—groups of reproductively isolated populations.
19.3K
Limits to Natural Selection01:38

Limits to Natural Selection

31.3K
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.
31.3K
Gene Flow02:39

Gene Flow

35.2K
Gene flow is the transfer of genes among populations, resulting from either the dispersal of gametes or from the migration of individuals.
35.2K
Conservation of Declining Populations02:07

Conservation of Declining Populations

9.6K
Conservation of declining population focuses on ways of detecting, diagnosing, and halting a population decline. The approach uses methods to prevent populations from going extinct.
9.6K

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

The crucible of resilience: hormesis as the unifying principle of evolution, genetics, and epigenetics.

Archives of toxicology·2026
Same author

Hormesis in biomedical and toxicological models: A generalizable phenomenon induced by per- and polyfluoroalkyl agents.

Chemico-biological interactions·2026
Same author

Canine environmental health: An EPA blind spot? Canine physiology, environmental exposure, and the regulatory gap in U.S. policy.

Regulatory toxicology and pharmacology : RTP·2026
Same author

Hormetic effects of per- and polyfluoroalkyl substances on ecologically relevant animal models: Generality, quantitative features, and risk assessment implications.

Environmental pollution (Barking, Essex : 1987)·2026
Same author

How the US NAS BEAR I Genetics Panel scientific misconduct could have been avoided, but was not.

Journal of occupational and environmental hygiene·2026
Same author

BEAR I Genetics Panel: An unexpected and troubling historical twist: The untold story of Hermann Muller's significant scientific confusion.

Journal of occupational and environmental hygiene·2026

Related Experiment Video

Updated: Jul 11, 2025

Protocol for Assessing the Relative Effects of Environment and Genetics on Antler and Body Growth for a Long-lived Cervid
09:09

Protocol for Assessing the Relative Effects of Environment and Genetics on Antler and Body Growth for a Long-lived Cervid

Published on: August 8, 2017

7.4K

Muller's genetic load/species extinction hypothesis.

Edward J Calabrese1, Paul B Selby2

  • 1School of Public Health and Health Sciences, Department of Environmental Health Sciences, Morrill I, N344, University of Massachusetts, Amherst, MA, 01003, USA.

Environmental Research
|November 12, 2023
PubMed
Summary

Extensive mouse studies failed to support Hermann Muller's genetic load hypothesis, finding no significant species extinction risks from ionizing radiation accumulation. Modern data further challenges the linear no-threshold model assumptions.

Keywords:
Genetic loadHermann MullerIonizing radiationLinear no-threshold dose responseRecessive mutationsSpecies extinction

More Related Videos

A Strategy to Identify de Novo Mutations in Common Disorders such as Autism and Schizophrenia
05:51

A Strategy to Identify de Novo Mutations in Common Disorders such as Autism and Schizophrenia

Published on: June 15, 2011

25.9K
Mass-Rearing and Molecular Studies in Tortricidae Pest Insects
06:22

Mass-Rearing and Molecular Studies in Tortricidae Pest Insects

Published on: March 25, 2022

2.8K

Related Experiment Videos

Last Updated: Jul 11, 2025

Protocol for Assessing the Relative Effects of Environment and Genetics on Antler and Body Growth for a Long-lived Cervid
09:09

Protocol for Assessing the Relative Effects of Environment and Genetics on Antler and Body Growth for a Long-lived Cervid

Published on: August 8, 2017

7.4K
A Strategy to Identify de Novo Mutations in Common Disorders such as Autism and Schizophrenia
05:51

A Strategy to Identify de Novo Mutations in Common Disorders such as Autism and Schizophrenia

Published on: June 15, 2011

25.9K
Mass-Rearing and Molecular Studies in Tortricidae Pest Insects
06:22

Mass-Rearing and Molecular Studies in Tortricidae Pest Insects

Published on: March 25, 2022

2.8K

Area of Science:

  • Radiation biology
  • Genetics
  • Evolutionary biology

Background:

  • Hermann Muller's genetic load hypothesis proposed species extinction risks from accumulated recessive genes due to ionizing radiation.
  • Extensive multi-generational mouse studies were conducted to test this hypothesis.
  • The hypothesis suggested potential deterioration or extinction of species over time.

Purpose of the Study:

  • To re-examine Muller's genetic load hypothesis.
  • To evaluate the methodologies and significance of past experimental findings.
  • To assess the validity of the hypothesis in light of new data.

Main Methods:

  • Review of long-term mouse radiation experiments (e.g., 82 generations).
  • Analysis of data from studies on mice, rats, and swine.
  • Evaluation of recent data on radiation-induced dominant mutations in mice.

Main Results:

  • Decades-long mouse studies (over 82 generations) showed no significant effects on reproductive fitness or longevity.
  • Numerous global studies failed to find convincing evidence supporting the genetic load theory.
  • Recent data on radiation-induced skeletal mutations in mice contradict cumulative and linear no-threshold assumptions.

Conclusions:

  • Muller's genetic load hypothesis, predicting species extinction from radiation-induced gene accumulation, is not supported by extensive experimental evidence.
  • The linear no-threshold (LNT) model and assumptions of generational accumulation of harmful mutations are challenged by current data.
  • Radiation risk assessments should reconsider the foundational assumptions of the genetic load hypothesis.