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1 .This is Scientific American 60-Second Science. I'm Erika Beras. Got a minute?

2 .The dust that accumulates in the corners of your house does more than just cause allergies and aggravation,

3 .it's also teeming with clues about where you live and who you live with.

4 .That's the finding of a study in the Proceedings of the Royal Society B.

5 .Researchers had volunteers at nearly 1,200 homes across the U.S.collect indoor and outdoor dust samples.

6 .The average home's dust contains about 5,000 types of bacteria and 2,000 types of fungi.

7 .The fungi gave away a lot about a home's location.

8 .Different regions have different fungal populations, and thus so do houses within those regions.

9 .For example, dwellings around the Great Lakes had very different fungi than did homes in Arizona,

10 .because most household fungi originate outside and come in either on people's clothes or through windows and doors.

11 .As for the bacteria, those were strong indicators of the identity of the home's residents.

12 .Much of the bacteria was shed by the human body and was a pretty good indicator of a home's gender ratio.

13 .The single-celled organisms also showed whether a pet shared the home, cats and dogs make their own contributions to the indoor bacterial menagerie.

14 .The research could inform forensic investigations and allergy studies.

15 .In the meantime, what can we take from these findings?

16 .Well, you can clean up dust but you can't change its composition.

17 .That is, unless you move. Or make some changes in the pets and people you live with.

18 .Thanks for the minute, for Scientific American 60-Second Science.I'm Erika Beras.