Genetic variation in Holocene bowhead whales from Svalbard.

Area of Science:

• Marine Biology
• Population Genetics
• Arctic Wildlife

Background:

• Bowhead whales (Balaena mysticetus) are Arctic cetaceans historically divided into five stocks.
• Centuries of exploitation have severely depleted all bowhead whale populations.
• The Spitsbergen stock is nearly extinct, prompting investigation into its ancestral origins.

Purpose of the Study:

• To analyze nucleotide sequence variation in the mitochondrial control region of ancient bowhead whale remains from Svalbard.
• To compare genetic diversity and haplotype frequencies between ancient Spitsbergen and extant Bering-Chukchi-Beaufort (BCB) stocks.
• To assess historical gene flow and evaluate the current stock structure of Arctic bowhead whales.

Main Methods:

• DNA extraction and sequencing of the mitochondrial control region from 99 bowhead whale bone remains.
• Radiocarbon dating (14C) of bone samples to establish a temporal framework (up to 50,000 years BP).
• Analysis of genetic diversity, haplotype diversity, nucleotide diversity, and population differentiation (F(ST), K(ST)).

Main Results:

• Fifty-eight unique haplotypes were identified among the ancient Svalbard samples.
• Abundant haplotypes in the Spitsbergen samples matched those found in the extant BCB stock.
• Low genetic differentiation (F(ST), K(ST)) and minor differences in nucleotide and haplotype diversity were observed between Spitsbergen and BCB stocks.

Conclusions:

• The historic Spitsbergen stock likely possessed genetic diversity comparable to the current BCB stock.
• Similarities in haplotypes suggest significant historical migration between Svalbard and BCB bowhead whale populations.
• Findings challenge the current designation of five distinct Arctic bowhead whale stocks, indicating potential intermixing.