The tiny mites that live in human resources and mate on our face at night are becoming so simplistic organisms, due to their unusual way of life, that they may soon become one with humans, according to new research. Mites are transmitted at birth and are transmitted by almost every human being, with numbers peaking in adults as pores grow. They are about 0.3 mm long, are located in the hair follicles on the face and nipples, including the eyelashes, and eat the sebum that is naturally released by cells into the pores. They become active at night and move between the follicles they want to mate with. The first genome sequencing study of D. folliculorum found that their individual existence and subsequent endogamy causes them to shed unnecessary genes and cells and move on from external parasites to internal symbionts. Dr Alejandra Perotti, Associate Professor of Invertebrate Biology at the University of Reading, who co-led the study, said: within the resources. “These changes in their DNA have led to some unusual features and behaviors in the body.” Mites Demodex folliculorum under a walking microscope. Credit: University of Reading An in-depth study of Demodex folliculorum DNA revealed:

Due to their isolated existence, no exposure to external threats, no competition for host infestations and no encounters with other mites with different genes, the genetic reduction made them extremely simple organisms with tiny legs fed by just 3 single-celled muscles. They survive on the minimal protein repertoire – the lowest number ever seen in it and related species. This gene reduction is also the reason for their nocturnal behavior. Mites lack UV protection and have lost the gene that causes animals to wake up to daylight. They have also been left unable to produce melatonin – a compound that makes small invertebrates active at night – however, they are able to feed overnight mating sessions using melatonin secreted by human skin at dusk. Their unique gene arrangement also results in the mites’ unusual mating habits. Their reproductive organs have moved forward and the males have a penis that protrudes upwards from the front of their body, which means that they must be placed below the female when mating and mating as they both cling to the human hair. One of their genes has been reversed, giving them a specific arrangement of mouthpieces that protrude particularly to collect food. This helps them survive at a young age. Mites have much more cells at a young age compared to their adult stage. This contradicts the previous hypothesis that parasitic animals reduce their number of cells early in development. Researchers say this is the first step in making mites live together. Lack of exposure to potential mates that could add new genes to their offspring may have put the mites on an evolutionary impasse and possible extinction. This has been observed in bacteria that lived inside cells in the past, but never in an animal. Some researchers have suggested that mites do not have an anus and therefore must accumulate all their feces during their lifetime before releasing them when they die, causing inflammation of the skin. The new study, however, confirmed that they have anus and thus have been unfairly blamed for many skin conditions.

                  The picture shows an unusually placed penis of a Demodex folliculorum mite.  Credit: University of Reading                                       Microscope image of the posterior end of the anus of a Demodex folliculorum mite.  The presence of anus in this mite had been wrongly ignored by some before, but this study confirmed its presence.  Credit: University of Reading

The research was conducted by Bangor University and the University of Reading, in collaboration with the University of Valencia, the University of Vienna and the National University of San Juan. Published in the magazine Molecular Biology and Evolution. Dr. Henk Braig, co-lead author at Bangor University and San Juan National University, said: “Mites have been blamed for many things. A long relationship with humans may suggest that they could also have simple but important beneficial roles. , for example, in keeping the resources in our face disconnected “. New research on dust mites and respiratory infections More info: Gilbert Smith et al, Human follicular mites: Exoparasites become symbiotic, Molecular Biology and Evolution (2022). DOI: 10.1093 / molbev / msac125 Provided by the University of Reading Report: The secret lives of mites on the skin of our faces (2022, June 21) retrieved on June 22, 2022 by
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