Organization and distribution of glomeruli in the bowhead whale olfactory bulb.

Title

Organization and distribution of glomeruli in the bowhead whale olfactory bulb.

Creator

Kishida Takushi; Thewissen J G M; Usip Sharon; Suydam Robert S; George John C

Publisher

PeerJ

Date

2015
1905-7

Description

Although modern baleen whales (Mysticeti) retain a functional olfactory system that includes olfactory bulbs, cranial nerve I and olfactory receptor genes, their olfactory capabilities have been reduced to a great degree. This reduction likely occurred as a selective response to their fully aquatic lifestyle. The glomeruli that occur in the olfactory bulb can be divided into two non-overlapping domains, a dorsal domain and a ventral domain. Recent molecular studies revealed that all modern whales have lost olfactory receptor genes and marker genes that are specific to the dorsal domain. Here we show that olfactory bulbs of bowhead whales (Balaena mysticetus) lack glomeruli on the dorsal side, consistent with the molecular data. In addition, we estimate that there are more than 4,000 glomeruli elsewhere in the bowhead whale olfactory bulb, which is surprising given that bowhead whales possess only 80 intact olfactory receptor genes. Olfactory sensory neurons that express the same olfactory receptors in rodents generally project to two specific glomeruli in an olfactory bulb, implying an approximate 1:2 ratio of the number of olfactory receptors to the number of glomeruli. Here we show that this ratio does not apply to bowhead whales, reiterating the conceptual limits of using rodents as model organisms for understanding the initial coding of odor information among mammals.

Subject

Cetacea; Baleen whale; Brain; Mysticeti; Olfactory marker protein; Olfactory receptor

Identifier

Rights

Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).

Pages

e897–e897

Volume

3

Citation

Kishida Takushi; Thewissen J G M; Usip Sharon; Suydam Robert S; George John C, “Organization and distribution of glomeruli in the bowhead whale olfactory bulb.,” NEOMED Bibliography Database, accessed February 28, 2021, https://neomed.omeka.net/items/show/5273.

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