Titan Arum, or Corpse Flower

This particular specimen was unfortunately not yet in bloom.  The Corpse Flower also known as the Titan Arum is best known for the smell it emits when in bloom.  It only blooms for 24 to 48 hours and it emits a smell that can range from rotting garbage to a dead corpse.  When I viewed it on Wednesday, the petals known as the spathe were wrapped around a very large hollow stem known as a spadix.  On the outside the spathe were green and you could just see the deep burgundy fray of the interior portion of the spathe.  The corpse flower not only emits a rotting meat fragrance when the spathe finally opens.  The flower's deep red or burgundy color and texture mimic the texture and appearance of rotting meat.  Moreover, during bloom the spadix heats up to the about 98 degrees Farenheit, which helps the perfume permeate the air and further seals the illusion of rotting meat.  All these attributes during bloom will then attract carrion-eating beetles and Flesh Flies that it turn pollinate the Corpse Flower in its native tropical forest clime in Sumatra.

After viewing the almost three foot Corpse flower personally, I have been following the daily blog about its progress on the Friend of the Greenhouse at  www.fotgh.com.  The blog has been updated faithfully by the Greenhouse Manager, Martin Marhoot.  Early last week the flower debunked experts by staying closed on the day they had predicted for it to open.  It is further being perplexing by given not a rancid odor but one quite sweet and familiar – that of chocolate!  This morning, which is Friday, July 3^rd as I write this, It started to emit this odor.  The spadix also increased in girth and it looks now like the spathes will relax and open just in time for fourth of July  What kind of scent will waft through Greenhouse is now up for debate.

Love is in the air

We've known for awhile that animals find their "true love" partly through smells. One of the things they are sensing is whether the potential mate has a different set of MHC genes.

MHC genes are a big part of our immune system. These genes are used to create the huge number of antibodies that we each make to battle bacteria, viruses, etc. Everyone has a different set of these antibodies.

The more varied your MHC genes are, the more invaders your immune system can recognize and defeat. So two parents with very different MHC genes will have kids with immune systems that can recognize (and so defeat) lots of different kinds of bacteria and viruses. Parents with similar MHC genes will have kids with less varied immune systems. (This is a big reason why inbred animals are so sickly.)

Animals can tell about a potential mate's MHC genes through smell. And people might be able to do this as well.

Lots of experiments have been done where men or women sniff the sweaty t-shirts of members of the opposite sex to see which t-shirt smells better. If the potential mates are of the same ethnic group, the sniffers tend to prefer mates with very dissimilar MHC genes. If the potential mates were of different ethnic groups, the sniffers preferred mates with somewhat but not wildly dissimilar MHC genes.

The new study looked at a group of 30 European American couples from Utah and 30 Yoruba couples from Nigeria. Thankfully there was no sweat smelling involved. Instead the researchers compared the DNA between the spouses of each couple in many different places throughout their genome.

What they found was that for the Utah couples, the DNA around the MHC genes was much less alike than the DNA almost everywhere else. This did not appear to be the case for the Yoruba couples. This suggests that at least for these 30 couples from Utah, having a very different set of MHC genes may have been part of picking a spouse.

Why the difference between the Utahans and the Yorubans? It is hard to say without more data but one possibility has to do with how much of a role social factors play in picking a spouse in each society. Perhaps the European Americans are freer to choose a mate. If this is the case, then they might be more likely to follow some sort of biological imperative.

Another possibility is that this smell test is only a big deal if the potential mates are all very similar to start with. The Utah couples all had pretty similar DNA to each other to begin with. The Yoruba couples' DNA was less alike.

Of course, this is a total of 60 couples and so is in no way exhaustive and may be proven wrong tomorrow. But it adds to a growing pile of evidence that suggests how mate selection works at the biological level. And it shows the wide range of things we can learn about ourselves by studying our DNA in great detail. Maybe it even gives perfume companies some ideas too.