The Straight Dope: How useful are at-home DNA tests?

[View this message as a web page]( [The Straight Dope]( 10/06/2017 Dear Cecil: Lots of ads on TV these days for various DNA test kits. You send a sample off to the company and they tell you … what? What are they actually telling you? Is this real scientific exploration or just intrusive data mining? — Jenny Cecil replies: If you’re suggesting the as-seen-on-TV approach might not be the best way to understand the most complex, private, and fundamental parts of your personal makeup, Jenny, you might be onto something. In hospitals and laboratories, the field of genetic testing is still something like the Wild West. In your bathroom, it’s practically the O.K. Corral. For more, see: [( STRAIGHT DOPE STAFF REPORT — 10/18/2001 Dear Straight Dope: My household has had a recent rash of giant man-eating spider attacks (as is common in early fall) that only I, recently knighted Sir Mikey the Spiderslayer, have been able to neutralize. Prompted by the insistence of my girlfriend that she had once been bitten by a spider and developed itchy welts and a rash, and that her father had captured the monster which he identified as the poisonous hobo spider, I hit the e-books and searched several sites over as many hours and gathered what information I could about these spiders. I did this because I was skeptical of dangerous spiders around these parts (I live 30 miles east of Seattle) as we dwell thousands of miles away from the range of the brown recluse and the black widow (reportedly the only dangerous spiders in the U.S.). I identified the spiders we saw as giant house spiders or common house spiders, deemed "completely harmless" in all sites from which I culled information. I also have heard somewhere that "spider bites" — itchy little welts, like bug bites, especially with paired raised bumps — are a myth. My gut feeling still says so, because spiders have a completely different type of poison than fire ants, bees, ticks, gnats, mosquitoes and other potential bite-mes. The bites of the other bugs are designed to cause irritation as means of defense, while spider venom is designed to liquefy prey flesh — thus the necrotic reaction to poisonous spider bites and eventual sloughing of skin. This led me to further doubt my girlfriend's self-diagnosis, as the reaction to severe spider poison includes initial painlessness (she said she had immediate itching), induration (hardening) within 30 minutes, erythema (redness) for up to 12 cm around site, swelling, ulceration, migraines, sloughing of skin, deep rooted necrosis (tissue death) in fatty tissue, and the like, all of which she confirmed negative. Furthermore, in my own experience handling spiders of many types bare-handed — including wolf spiders, garden spiders, house spiders, cellar spiders, giant monster cat-size human bloodsucker spiders and so forth — I have never been bitten or seen any ill effects worth noting, even though I watched while some of the big ones scraped their fangs against the flesh on top of my fingers. I am only 19 years old and spend most of my time in front of the computer, so my hands aren't calloused at all either. Finally, my girlfriend is an ultra-arachnophobe, which you and I know can cause pretty big gaps in reasoning that aren't easily filled by cool logic. I have since discovered that my sense of safety was false — the hobo spider does indeed inhabit the Pacific Northwest, as far north as the Alaskan panhandle, south to northern California and east as far as Utah. Okay. But the drama continues. Information I obtained from the University of California ([() seemed to indicate that there was no proof of any sort of danger from the hobo spider, citing actual venom tests, and I consider this a reliable source. However, all the other sites I searched, including other respectable medical, CDC and university sites, seemed to agree that the hobo spider, while no confirmed deaths were reported, does have a necrotic bite and could be dangerous. Many of the sites I visited listed confirmed reports of bites from hobo spiders. To further compound my frustrations, I called my local pest control center, and they didn't even bother to come and identify my living specimen that I captured last night, completely sure that it was not a hobo spider, unless I had had something imported from another state. So my attempt to secure an arachnologist was foiled. So my question is two-fold: firstly, do spider bites really occur that are merely itchy little welts that any common house spider can inflict, and if so, what other kinds of spiders can cause this; and secondly, what's the deal on the hobo spider? Do they inhabit wetlands like I live in, as my pest-control expert doubted? Are they being driven out by house spider competition? Are they truly poisonous? — mikey SDStaff Doug replies: I'm friends with Rick Vetter, the person who wrote the above-mentioned Web page. Rick has sent along the following response: The hobo spider does indeed live in Washington. I am currently doing a study on its distribution with help from lots of folks in the northwestern U.S. and British Columbia. The Web site that says the hobo isn't dangerous is mine, but the reader has misinterpreted what I have written. In regard to hobo bites, new research HAS NOT duplicated the original experiments showing that the hobo spider has a poisonous venom that is capable of causing necrosis. The original research pressed actual spiders into shaved rabbit flesh until the spiders bit, and necrotic wounds developed. However, recent unpublished research involving mechanically-milked hobo venom (thereby eliminating any confounding factors like digestive regurgitant or bacterial infection), got no necrosis whatsoever in rabbits, using hobos from America and Europe. That said … For more, see: [( STRAIGHT DOPE CLASSIC — 03/18/2005 Dear Cecil: Is brainwashing possible? How does it work? Does the government really use it? How would I go about brainwashing someone? — JRMecca, via e-mail Cecil replies: Let's define our terms. If by brainwashed you mean "presenting a zombie-like appearance and having no interest in normal human contact," all you have to do is sit your subject down with a Game Boy. However, if you're looking for something a little more advanced, e.g., a preprogrammed assassin as depicted in the 1962 movie and 2004 remake The Manchurian Candidate, that could be a little tougher to deliver on For more, see: [( YOUR AD HERE! Your direct line to thousands of the smartest, hippest people on the planet, plus a few total dipsticks. For rates and details contact Rich at [rhummel@suntimes.com](. Copyright © 2017 Sun-Times Media, LLC. This email was sent by The Straight Dope, Sun-Times Media, LLC., 350 N. Orleans, 10th Floor, Chicago, IL 60654 [Unsubscribe/update preferences]( This email was sent to {EMAIL}. To change or update your newsletter subscription preferences, or to unsubscribe from all Chicago Reader and Straight Dope newsletters and promotional communications, [click here](. Please allow 72 hours for this change to take effect.