Glabrousness (from the Latinglaber meaning "bald", "hairless", "shaved", "smooth") is the technical term for a lack of hair, down, setae, trichomes or other such covering. A glabrous surface may be a natural characteristic of all or part of a plant or animal, or be due to loss because of a physical condition, such as alopecia universalis in humans, which causes hair to fall out or not regrow.
Glabrousness or otherwise, of leaves, stems, and fruit is a feature commonly mentioned in plant keys; in botany and mycology, a glabrousmorphological feature is one that is smooth and may be glossy. It has no bristles or hair-like structures such as trichomes. In anything like the zoological sense, no plants or fungi have hair or wool, although some structures may resemble such materials.
The term "glabrous" strictly applies only to features that lack trichomes at all times. When an organ bears trichomes at first, but loses them with age, the term used is glabrescent.
In the model plant Arabidopsis thaliana, trichome formation is initiated by the GLABROUS1 protein. Knockouts of the corresponding gene lead to glabrous plants. This phenotype has already been used in gene editing experiments and might be of interest as a visual marker for plant research to improve gene editing methods such as CRISPR/Cas9.[1][2]
The Naked mole-rat (Heterocephalus glaber) has evolved skin lacking in general, pelagic hair covering, yet has retained long, very sparsely scattered tactile hairs over its body.[3] Glabrousness is a trait that may be associated with neoteny.[citation needed]
Within entomology, the term glabrous is used to refer to those parts of an insect's body with are lacking in setae (bristles) or scales.[5]
^ abPrescott, Tony J.; Ahissar, Ehud; Izhikevich, Eugene, eds. (2016). Scholarpedia of Touch. San Diego, USA: Atlantis Press. p. 9. ISBN978-94-6239-133-8. Retrieved 21 February 2017.
^Linden, David, J. (March 2015). "Chapter 2". Touch: The Science of Hand, Heart and Mind. Viking. ISBN978-0241184035.{{cite book}}: CS1 maint: multiple names: authors list (link)