Chapter 20 - Molecular insights into anatomy and physiology
Creator
Cooper LN; Gorbunova V
Publisher
The Bowhead Whale
Date
2021
Description
Bowhead whales are some of the largest animals that occupy the Arctic Circle. Despite the challenges of living and giving birth in icy waters, having huge blubber stores, eating a fat-rich diet, and undergoing arduous migrations, bowheads achieved the longest known life span of mammals of 268 years. Their longevity is extended by fixed mutations that prevent DNA damage and cancer and through evolutionary modifications to their metabolism that compensate for an oxygen-poor environment. Recently, the bowhead genome and transcriptome libraries were made publicly available for study. Analyses suggest that their life span has been extended by evolutionary changes that result in the upregulation of DNA repair pathways. Molecular biologists are now undertaking laboratory experiments with whale samples that are informed by the bowhead genome and transcriptome to tackle questions that were inaccessible using classical model organisms such as rodents or fish. Biomedical researchers are also applying insights gained from research on bowheads into investigations of potential therapies for aging, senescence, and cancer. Moreover, researchers are using these results to inform our understanding of the evolutionary history of these traits. This chapter reviews the molecular basis for bowhead whale longevity and survival in their unique habitat and offers insights for further exploration into the molecular mechanisms that shape the extraordinary lives of these animals.
Chapter 20 - Molecular insights into anatomy and physiology
Creator
Cooper LN; Gorbunova V
Publisher
The Bowhead Whale
Date
2021
2021-01-01
Description
Bowhead whales are some of the largest animals that occupy the Arctic Circle. Despite the challenges of living and giving birth in icy waters, having huge blubber stores, eating a fat-rich diet, and undergoing arduous migrations, bowheads achieved the longest known life span of mammals of 268 years. Their longevity is extended by fixed mutations that prevent DNA damage and cancer and through evolutionary modifications to their metabolism that compensate for an oxygen-poor environment. Recently, the bowhead genome and transcriptome libraries were made publicly available for study. Analyses suggest that their life span has been extended by evolutionary changes that result in the upregulation of DNA repair pathways. Molecular biologists are now undertaking laboratory experiments with whale samples that are informed by the bowhead genome and transcriptome to tackle questions that were inaccessible using classical model organisms such as rodents or fish. Biomedical researchers are also applying insights gained from research on bowheads into investigations of potential therapies for aging, senescence, and cancer. Moreover, researchers are using these results to inform our understanding of the evolutionary history of these traits. This chapter reviews the molecular basis for bowhead whale longevity and survival in their unique habitat and offers insights for further exploration into the molecular mechanisms that shape the extraordinary lives of these animals.
Beyond thermoregulation: metabolic function of cetacean blubber in migrating bowhead and beluga whales.
Creator
Ball H C; Londraville R L; Prokop J W; George John C; Suydam R S; Vinyard C; Thewissen J G M; Duff R J
Publisher
Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology
Date
2017
2017-01
Description
The processes of lipid deposition and utilization, via the gene leptin (Lep), are poorly understood in taxa with varying degrees of adipose storage. This study examines how these systems may have adapted in marine aquatic environments inhabited by cetaceans. Bowhead (Balaena mysticetus) and beluga whales (Delphinapterus leucas) are ideal study animals-they possess large subcutaneous adipose stores (blubber) and undergo bi-annual migrations concurrent with variations in food availability. To answer long-standing questions regarding how (or if) energy and lipid utilization adapted to aquatic stressors, we quantified variations in gene transcripts critical to lipid metabolism related to season, age, and blubber depth. We predicted leptin tertiary structure conservation and assessed inter-specific variations in Lep transcript numbers between bowheads and other mammals. Our study is the first to identify seasonal and age-related variations in Lep and lipolysis in these cetaceans. While Lep transcripts and protein oscillate with season in adult bowheads reminiscent of hibernating mammals, transcript levels reach up to 10 times higher in bowheads than any other mammal. Data from immature bowheads are consistent with the hypothesis that short baleen inhibits efficient feeding. Lipolysis transcripts also indicate young Fall bowheads and those sampled during Spring months limit energy utilization. These novel data from rarely examined species expand the existing knowledge and offer unique insight into how the regulation of Lep and lipolysis has adapted to permit seasonal deposition and maintain vital blubber stores.
Seasonal and Ontogenetic Variation in Subcutaneous Adipose Of the Bowhead Whale (Balaena mysticetus).
Creator
Ball Hope C; Stavarz Madeline; Oldaker Jonathan; Usip Sharon; Londraville Richard L; George John C; Thewissen Johnannes G M; Duff Robert Joel
Publisher
Anatomical record (Hoboken, N.J. : 2007)
Date
2015
2015-08
Description
Cetacean evolution was shaped by an extraordinary land-to-sea transition in which the ancestors of whales became fully aquatic. As part of this transition, these mammals evolved unusually thick blubber which acts as a metabolic reservoir as well as an insulator and provides buoyancy and streamlining. This study describes blubber stratification and correlates it to seasonal variation, feeding patterns, and ontogeny in an arctic-adapted mysticete, the bowhead whale (Balaena mysticetus). Bowheads are unique among mammals for possessing the largest known blubber stores. We found that adipocyte numbers in bowheads, like other mammals, do not vary with season or feeding pattern but that adipocyte size and structural fiber densities do vary with blubber depth.