When ThruLines Numbers Don’t Make Sense

As genealogists, we often assume that DNA evidence should behave logically. The closer the ancestor, the more DNA matches we should see. The farther back we go, the fewer matches we should expect.

Usually, that’s true.

But sometimes Ancestry’s ThruLines produces results that leave us scratching our heads.

That happened recently while I was looking at my Hutchinson line.

The Question

My 2nd great-grandfather was Albert Hutchinson. Albert was likely the only child of Aaron Hutchinson and Sarah Merry Hutchinson, both of whom died while Albert was still young. In 1850, Albert appears in the household of Ephraim and Cynthia Finch, likely his aunt and uncle.

Looking at ThruLines, I found:

• 43 matches for Albert Hutchinson
• 43 matches for Aaron Hutchinson
• 43 matches for Sarah Merry
• but only 33 matches for Aaron’s parents, Aaron and Hannah Hutchinson
• and 35 matches for Sarah’s parents, Whiting and Elizabeth Merry

At first glance, that seemed odd.

If those 43 matches connect through Albert, and Albert is Aaron’s son, shouldn’t all 43 continue upward to Aaron’s parents?

Apparently not.

Understanding What ThruLines Counts

One of the first lessons here is that the red ThruLines numbers do not represent all DNA inherited from an ancestor.

Instead, they represent:

DNA matches Ancestry can currently assign to that ancestor through available tree connections.

That’s a big difference.

A DNA match may connect to Albert because the tree path is clear:

DNA Match → Parent → Grandparent → Albert Hutchinson

But if that same tree does not extend one generation farther, or if public trees disagree about Albert’s parentage, the match may stop there.

That means the drop in numbers does not necessarily reflect genetics. It often reflects tree completeness.

My Workflow: Common Ancestor Downward

This discussion made me think about how I document descendants for DNA work.

When working with collateral lines, I usually document from the common ancestor downward, rather than starting with a DNA match and working backward.

For example:

Aaron and Hannah Hutchinson
↓
their children
↓
grandchildren
↓
later descendants

The advantage is obvious: when a DNA match appears, I can ask:

Where does this person fit in my documented descendancy?

instead of relying entirely on Ancestry’s suggestion.

This is essentially FAN-club research applied to DNA.

Would More Descendancy Research Help?

Possibly.

If I document more descendants of:

• Aaron and Hannah Hutchinson
• Whiting and Elizabeth Merry

and upload those descendants through RootsMagic TreeShare to my Ancestry tree, Ancestry may be able to make additional connections.

But there are no guarantees.

ThruLines also depends on:

• whether DNA matches have usable trees
• whether those trees are public
• whether the ancestral paths are accurate
• whether Ancestry’s algorithm accepts the connection

So the real benefit may not be increasing the red numbers.

The bigger benefit is improving my own ability to interpret the evidence.

Are All Matches Equally Valuable?

Definitely not.

This may be the biggest takeaway.

A ThruLines count of 43 looks impressive—but those matches are not all equally useful.

Some may have:

• private trees
• incomplete trees
• copied trees
• questionable parentage

One carefully documented DNA match can be far more valuable than a dozen vague ThruLines hints.

For example, a proven descendant of a sibling of Aaron Hutchinson would provide much stronger support for that family structure than multiple poorly documented matches.

In other words:

The identity of the matches matters more than the red number.

My Documentation Strategy

For descendancy work, I usually stick with:

• census records
• Find a Grave
• obituaries

Those sources are often enough to build a practical descendant framework.

If a particular DNA match becomes important to a proof argument, then I dig deeper into:

• probate records
• vital records
• marriage records
• land records
• Social Security applications
• other supporting evidence

That approach keeps the work manageable.

Broad documentation for mapping.

Deep documentation for proof.

Final Thoughts

ThruLines is a wonderful clue-generating tool—but it is still a clue tool.

The red numbers can suggest where descendant lines may be underdeveloped, but they do not prove relationships.

As genealogists, we still need to do what genealogists do best:

document, analyze, compare, and question.

And sometimes, ask why 43 suddenly becomes 33.

---

This Hutchinson puzzle reminded me that DNA tools are most useful when paired with traditional genealogical methods—not treated as replacements for them.