Abstract
Antifreeze proteins inhibit ice growth and are crucial for the survival of supercooled fish living in icy seawater. Of the four antifreeze protein types found in fishes, the globular type III from eelpouts is the one restricted to a single infraorder (Zoarcales), which is the only clade know to have antifreeze protein-producing species at both poles. Our analysis of over 60 unique antifreeze protein gene sequences from several Zoarcales species indicates this gene family arose around 18 Ma ago, in the Northern Hemisphere, supporting recent data suggesting that the Arctic Seas were ice-laden earlier than originally thought. The Antarctic was subject to widespread glaciation over 30 Ma and the Notothenioid fishes that produce an unrelated antifreeze glycoprotein extensively exploited the adjoining seas. We show that species from one Zoarcales family only encroached on this niche in the last few Ma, entering an environment already dominated by ice-resistant fishes, long after the onset of glaciation. As eelpouts are one of the dominant benthic fish groups of the deep ocean, they likely migrated from the north to Antarctica via the cold depths, losing all but the fully active isoform gene along the way. In contrast, northern species have retained both the fully active (QAE) and partially active (SP) isoforms for at least 15 Ma, which suggests that the combination of isoforms is functionally advantageous.
Highlights
Most marine teleosts are unable to inhabit ice-laden sea waters characteristic of polar and subpolar oceans because the temperature of the water (−1.9 ̊C) can be a full degree lower than the freezing point of their body fluids (−0.7 to −0.9 ̊C) [1]
Teleost fish that can survive and thrive in such environments do so by producing antifreeze proteins (AFPs) or glycoproteins (AFGPs) that bind to nascent ice crystals within their body fluids, thereby preventing their further growth that would result in death
Given the diverse evolutionary history of fish AFPs, we examined in this study several questions about type III AFPs
Summary
Most marine teleosts are unable to inhabit ice-laden sea waters characteristic of polar and subpolar oceans because the temperature of the water (−1.9 ̊C) can be a full degree lower than the freezing point of their body fluids (−0.7 to −0.9 ̊C) [1]. In contrast such environmental conditions pose no risk to most invertebrates as their freezing points are usually the same as that of sea water [2]. Fish antifreeze protein gene changes reveals migration and climate alteration within the last 20 Ma corresponding protein accession numbers are ALL26673-ALL26680 Teleost fish that can survive and thrive in such environments do so by producing antifreeze proteins (AFPs) or glycoproteins (AFGPs) that bind to nascent ice crystals within their body fluids, thereby preventing their further growth that would result in death
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
