How DNA from Living Descendants Helped Identify Doomed Franklin Expedition Sailors

Introduction

In 1845, Sir John Franklin led two ships, HMS Erebus and HMS Terror, on an ill-fated voyage to find the Northwest Passage. All 129 crew members perished in the Arctic, leaving behind a mystery that captivated historians for nearly two centuries. Recent advances in DNA technology, combined with living descendants, have now identified four more sailors. This step-by-step guide explains how this remarkable identification process works, revealing clues about how the men tried to find safety before their tragic end.

How DNA from Living Descendants Helped Identify Doomed Franklin Expedition Sailors — Source: www.livescience.com

What You Need

Historical records: Crew manifests, diaries, and notes from search expeditions (e.g., from sailors' graves or written accounts).
DNA samples from living descendants: Buccal swabs or blood samples from people who can trace lineage to expedition members (maternal or paternal lines).
Ancient DNA (aDNA) extraction kit: Specialized tools to retrieve DNA from skeletal remains or preserved tissue, often found in permafrost.
Genetic analysis lab: Facilities with PCR machines, sequencers, and bioinformatics software to compare DNA profiles.
Reference database: Y-chromosome, mitochondrial, or autosomal DNA markers from known descendant samples.
Ethical approval: Permissions from local communities, descendant families, and historical societies.

Step-by-Step Guide

Step 1: Locate and Document Burial Sites or Remains

Start by reviewing historical accounts of the Franklin expedition. Researchers have located graves on Beechey Island (where three crew members were buried in 1846) and scattered remains along the route where survivors attempted to walk to safety (e.g., at King William Island). Use archaeological surveys to map these locations. The goal is to identify which skeletal remains likely belong to specific crew members based on artifacts, clothing, or physical evidence.

Step 2: Identify and Recruit Living Descendants

Trace genealogical records—birth, marriage, death certificates, and old letters—to find individuals who are direct descendants of the Franklin sailors. Focus on mitochondrial DNA (passed from mothers to all children) for maternal lines, or Y-chromosome DNA (passed from fathers to sons) for paternal lines. Contact these descendants through genealogy societies, social media, or newspaper calls. Ask them to provide a simple cheek swab or blood sample, and obtain informed consent for research.

Step 3: Extract Ancient DNA (aDNA) from Remains

In a sterile lab, take small samples (e.g., a tooth root or a fragment of the femur) from the Franklin expedition skeletons. The cold Arctic permafrost often preserves DNA, but it is highly fragmented. Use a specialized extraction protocol:

Clean the bone surface to remove modern contaminants.
Grind the bone into a fine powder.
Add a digestion buffer and proteinase K to release DNA.
Purify the DNA using silica-based columns.
Amplify target regions (e.g., hypervariable segments of mitochondrial DNA or specific Y-STR markers) via PCR.

Step 4: Compare Genetic Profiles

Sequence the amplified DNA from the remains and from the living descendants. For maternal matches, compare the mitochondrial DNA sequences. For paternal matches, look at Y-chromosome short tandem repeats (STRs). Use statistical software to calculate the probability that a match is not coincidental. If the profiles share unique mutations or haplotypes, the identification is considered strong. In the Franklin case, researchers matched four sailors—such as John Doe (fictional example)—by linking aDNA from a skull to descendants living in Canada and the UK.

Step 5: Interpret the Clues About Their Final Days

Once identified, analyze the remains to infer the sailors' actions. For instance:

Cut marks on bones suggest cannibalism as a last-ditch survival measure.
Lead isotope levels from tooth enamel reveal possible lead poisoning from soldered cans.
DNA analysis of gut contents shows what they ate before death (e.g., seal or canned food).

Combine this with historical notes, like those left by rescue teams who found a deserted ship or a makeshift camp. The identified sailors’ positions on the trek indicate how far they got—revealing that some walked up to hundreds of kilometers, desperately trying to reach a Hudson's Bay Company outpost.

Tips for Success

Preserve samples carefully: aDNA degrades quickly; work in a clean room and use negative controls to avoid contamination.
Use multiple genetic markers: Combining mtDNA, Y-chromosome, and autosomal SNPs increases accuracy.
Respect descendant families: Share findings sensitively and involve them in the storytelling.
Collaborate with historians: Context from diaries of Frederick Crozier or surviving Inuit accounts enriches interpretation.
Plan for ethical hurdles: Obtain permissions from indigenous communities if remains are on their land.

By following these steps, researchers have not only put names to long-lost faces but also pieced together the tragic final chapter of the Franklin expedition. The next identifications may come from even smaller DNA fragments—or from descendants who haven't yet been found.

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