Fruit Fly Hearing as a Model for Human Hearing
Hearing loss is very common among the aging population. It affects about one out of three people over 65-years-old. According to the World Health Organization (WHO), in 2050 there will be over 900 million people who will experience hearing loss.
Fruit flies have also been shown to experience age-related hearing loss (presbycusis). These flies are a very versatile model of insects that are commonly used by researchers. A fruit fly’s hearing system is similar to a human’s hearing system, hence the reason why they are closely studied by analysts.
Fruit flies preserve their sensitive hearing abilities until late in their life. On average, a fruit fly lives for about 58 days. They can maintain their sensitive hearing abilities for about 50 days, which is about 85% of their life. Not only are fruit flies the best model for examining human age-related hearing loss, but analysts can also learn how humans can maintain their ability to hear.
An array of methods were used to test the networks of transcription factors (Proteins involved in the process of converting, or transcribing, DNA into RNA, or “master genes”). These master genes can manage other genes and coordinate crucial signaling pathways that protect the healthy hearing abilities of a fly for their life.
4 Key Genes to Maintaining Good Hearing
There are four genes in flies and humans that are vital to creating new nerve cells in the body, but they are also revealed to help preserve hearing and possibly other senses.
In the same way that there are chemical, internal, and physical processes that are involved in the development of the ears, there are separate processes within the body that takes care of ear maintenance. It was discovered that there are two resulting duplicates (paralogs) of existing developmental genes - not the developmental genes themselves - that help maintain the ability to hear.
Evolution can cause genes to duplicate. The result of the two copies are known as paralogs. Paralogs tend to functionally deviate, where one (or both) genes take on new positions. For example in the fully formed fruit fly ear, researchers discovered that one of the vital development genes had been replaced by its paralog when the fly’s ear became fully formed.
This may be a significant evolutionary process. The 19th-century recapitulation theory suggests that developmental history re-enacts the evolutionary history of an organism. An organ’s maintenance procedure is most likely part of a repetition of what it was intended to do during development. To keep ears youthful and in good health, this development may be partially repeated - but the paralogs of the developmental genes perform the operation.
The original master gene, known as the atonal, isn’t active in an adult fly’s ears, but the paralog, or the amos, is active. Rather than reiterate the developmental history or completely rebuild the ear from square one, it may be easier to improve the maintenance processes that are currently being used.
The study found that changing these paralogs in fruit flies could save their ears from different outcomes of age-related hearing loss. Fruit flies who had altered paralogs had similar hearing abilities as young fruit flies. This indicates that related gene therapies for humans may add some more years of healthy hearing.
If you, or a loved one, are experiencing hearing loss, please contact us at Pure Sound Hearing for a free hearing test and consultation.
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