A Variegated Tomato

Here's another tomato oddity to add to list this year:  a variegated tomato plant.  Didn't know that even existed?  Neither did I until a couple of months ago.
Shortly after transplanting the tomatoes into the raised beds, I noticed that one of the plants (an heirloom Opalka) had some white areas on its leaves.  My first instinct was to assume that the plant was experiencing a little sun scald, which seemed completely logical, given the fact that the squirrels had forced me to move all the tomatoes to the porch for the last week or two before they went into the ground.
But as time went on, even some of the new growth was emerging with the same white markings, and I knew it wasn't just a matter of sun exposure.   Around that same time, we had my family up to celebrate the June birthdays, so I had my brother (Mr. Ph.D in plant genetics) take a look at it.  He was a little stumped as well, guessing that it was either a random genetic mutation or some kind of virus that was causing the variegated leaves, and he was leaning towards virus on the basis that variegated tulips were originally caused by a virus before they were bred for that characteristic.
I spent a good amount of time Googling "tomato viruses" and scrolling through photos of abnormal tomato leaves, but I never could find an exact match, so in one last attempt to find a definitive answer before digging the tomato plant out of the garden (if it was a virus, I certainly didn't want to risk it spreading to the other plants), I posted a few photos in a gardening forum I belong to, to see if any of my fellow gardeners had any ideas.  One of them pointed me to this article, which is incredibly technical, but ultimately answered the question that, yes, sometimes tomatoes can grow variegated leaves (who knew!?).  
As I browsed through the article, the description was pretty much spot on with what I was observing in my garden:   There were both variegated and leaves with a normal appearance on the same plant.  The variegated leaves varied a bit, some of them having just a little bit of variegation, and others looking almost entirely white washed.  The lighter colored areas of the leaves had less cell structure, and were flat, compared to the greener parts of the leaves that looked just as you expect them to.  The variegation also extended to the stems of the corresponding leaves.
So I left the plant in the garden to grow.  It was somewhat stunted, and grew at a slower pace than the rest of the tomatoes in the garden (the number one reason my brother was leaning towards virus), but it did eventually bloom at set fruit (notice that even the sepals have some lighter stripes in them).  The fruit took a while to really start growing (they stayed about the size of the photo above for quite a while before they started to elongate, which you can also see had a little bit of a effect on the appearance once they started to grow in earnest).
Actually, I'm quite surprised at the number of tomatoes the plant has on it, given the fact that the article said most variegated plants are unfruitful.  Though none of them are anywhere near ripening yet, so time will tell (though I have no reason to believe that they won't ripen). If they do ripen, it's hard to say if the seeds in these tomatoes will be viable, and probably even less likely that will produce true to type, and grow another generation of variegated tomatoes, but it might be fun to see what does happen.  
As the season has gone on, the variegation in the new growth has become a little more subtle.  The new growth that continues to set on is much more normal in appearance, where earlier in the season, it seemed that the variegated leaves far out numbered the solid green ones (perhaps there is a connection between temperature and how the variegation is expressed?). 
As much as I had my doubts during it's slow-growing days, the plant has proven to be a pretty healthy plant.  It is still a little behind the other tomatoes (around 5 or 6' tall, compared to 7-8'), but at the same time, it has been growing much more densely than the other tomatoes, and without another "normal" Opalka growing right next to it, it's hard to say if that's just not the way this particular variety grows.  Regardless, it's been an interesting tomato plant to observe and I'm anxiously waiting to see what the fruit will do!