Evidence map›Paper›PMID 35724423›Full record

ArticleMolecular biology and evolution2022

Human follicular mites: Ectoparasites becoming symbionts.

Gilbert Smith, Alejandro Manzano Marín, Mariana Reyes-Prieto, Cátia Sofia Ribeiro Antunes, Victoria Ashworth, Obed Nanjul Goselle, Abdulhalem Abdulsamad A Jan, Andrés Moya, Amparo Latorre, M Alejandra Perotti and 1 more

Abstract read
In one paragraph

Article in Molecular biology and evolution, 2022. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 8 papers.

0numbers the graph read from it
0cells of the map it votes in
8citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

8 citing papers in PubMed.

  1. Review
  2. Article
  3. Article
  4. HALP score inOpen medicine (Warsaw, Poland) · 2025
    Article
  5. Reducing ocularFrontiers in allergy · 2025
    Article
  6. Epidemiological survey of two morphotypes ofParasite epidemiology and control · 2024
    Article
  7. Article
  8. Article
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

11 authors.

Gilbert SmithSchool of Natural Sciences, Bangor University, Bangor, Wales, United Kingdom.
Alejandro Manzano MarínCentre for Microbiology and Environmental Systems Science (CMESS), University of Vienna, Vienna, Austria.ORCID 0000-0002-0707-9052
Mariana Reyes-PrietoInstitute of Integrative Systems Biology (I2Sysbio), Universitat de València and Spanish Research Concil (CSIC), València, Spain.
Cátia Sofia Ribeiro AntunesSchool of Natural Sciences, Bangor University, Bangor, Wales, United Kingdom.
Victoria AshworthSchool of Natural Sciences, Bangor University, Bangor, Wales, United Kingdom.
Obed Nanjul GoselleSchool of Natural Sciences, Bangor University, Bangor, Wales, United Kingdom.
Abdulhalem Abdulsamad A JanSchool of Natural Sciences, Bangor University, Bangor, Wales, United Kingdom.
Andrés MoyaInstitute of Integrative Systems Biology (I2Sysbio), Universitat de València and Spanish Research Concil (CSIC), València, Spain.
Amparo LatorreInstitute of Integrative Systems Biology (I2Sysbio), Universitat de València and Spanish Research Concil (CSIC), València, Spain.
M Alejandra PerottiSchool of Biological Sciences, University of Reading, Reading, United Kingdom.ORCID 0000-0002-3769-7126
Henk R BraigSchool of Natural Sciences, Bangor University, Bangor, Wales, United Kingdom.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

Most humans carry mites in the hair follicles of their skin for their entire lives. Follicular mites are the only metazoans tha continuously live on humans. We propose that Demodex folliculorum (Acari) represents a transitional stage from a host-injuring obligate parasite to an obligate symbiont. Here, we describe the profound impact of this transition on the genome and physiology of the mite. Genome sequencing revealed that the permanent host association of D. folliculorum led to an extensive genome reduction through relaxed selection and genetic drift, resulting in the smallest number of protein-coding genes yet identified among panarthropods. Confocal microscopy revealed that this gene loss coincided with an extreme reduction in the number of cells. Single uninucleate muscle cells are sufficient to operate each of the three segments that form each walking leg. While it has been assumed that the reduction of the cell number in parasites starts early in development, we identified a greater total number of cells in the last developmental stage (nymph) than in the terminal adult stage, suggesting that reduction starts at the adult or ultimate stage of development. This is the first evolutionary step in an arthropod species adopting a reductive, parasitic or endosymbiotic lifestyle. Somatic nuclei show underreplication at the diploid stage. Novel eye structures or photoreceptors as well as a unique human host melatonin-guided day/night rhythm are proposed for the first time. The loss of DNA repair genes coupled with extreme endogamy might have set this mite species on an evolutionary dead-end trajectory.

Indexed as

Acaricircadian rhythmextinctiongenome erosionhuman microbiomephotoreceptor

Identifiers

PMID35724423
PMCPMC9218549

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Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.