Identical, but...not

Does anyone else have twins that are technically identical but look noticeably different? Ours are identical, but their hair and eye colors and some facial features are different. What do you say when strangers ask you how it's possible for identical twins to not be identical? I get asked all the time.

 

You could always baffle them and say, "They aren't Identical, they're Monozygotic!"

 

I'm confused... how can identical twins have different eye colors?

 

Huh, I never knew ID twins could have different eye colors and hair. I like the PP's answer about them being monozygotic.

Mona

 

I knew ID twins growing up that had "different" hair color. They started out more blonde, then one twin's darkened up years before the other one's. They ended up the same when they got older, though.

And I don't know this for sure, but I would think it possible for ID twins to have different eye colors. It's one of these "expression" things, where they have the same genes, but different aspects are expressed. If they are brown/dominant eye colored, it could be that one has brown eyes and one has hazel or "green" eyes; if they are blue/recessive eye colored, it is possible for one to have a brighter blue and one to be more green/blue or grey. But one blue, one brown is NOT possible.

 

My understanding is that ID twins can have different SHADES of hair and eye color. So, they would both need to be blond, but one could have slightly darker blond hair. Or both blue eyed but with different shades of blue. That would be a genotype (dna) vs phenotype (how the dna is "expressed") thing. But they can't have completely different colors (that is, you can't have one blond and one redhead or one with blue eyes and one with green).

 

It is possible for a person to have two different eye color so it is possible for id twins to have different eye colors. My id twins have different face shapes and are 5lbs and 3 inches different.

 

I read a really interesting article on this. This genetics expert talks about the fact that identical twins have the same DNA, but use it in different ways. They also have different environmental influences (that start in the womb!) and these play a part as well.
Here's a link to the article:

http://www.thetech.org/genetics/ask.php?id=142

Also, studies have shown that 98% of identical twins have the same eye color. So it is possible for them to be different, but quite rare. If your twins have different eye color and you have not had them tested to verify identical or fraternal, you may want to consider it based on those statistics.

 

I was thinking of getting T-shirts made up that say "We're not IDENTICAL, we just have the same DNA". Mine have different head shapes which makes their faces look a bit different. When they were very young, the differences were more pronounced and everyone (including DH & I) presumed they were fraternal. One also had more hair than the other making it look darker. They look considerably more alike now.

 

I too was under the assumption that while the ID twins could have different shades, it's very unlikely that they could have different color eyes, etc.

It is impossible to be sure if they are ID unless you've had a DNA test done....

Just my $.02

 

Eye color is controlled by several genes (we aren't sure how many) BUT because there are several genes involved any number of things can happen to 'turn on' or 'turn off' one of those genes. Environmental factors also change gene expression (how the gene 'looks') the easiest example is sun-tanning so you can chang eyour skin color by exposure to UV radiation. My point is that certainly people with the same genes can can different gene expression. As the past pp said if ONE person with the same genes in all their cells can have 2 eye colors presumably 2 people with the same genes can have 2 eye colors.

So if it were me I would launch into the genetic description and confuse them!!

 

RRTwins, thanks for posting that link! Great articles and answered a lot of questions that our family's been wondering the last few weeks. I've always wondered about the fingerprint thing.

Our girls look ID in photos, but in person the weight difference and hair thing makes them look so different. Also, they have the same features, but they use them in such different ways. Their smiles, for example, or the way they look at you.

 

Just curious, but are you sure they are identical? Did you have them DNA tested or did they share the same sac and/or placenta. I know it is VERY rare for ID twins to have different hair/eye color and I am wondering if your twins "appeared" to share the same placenta but it actually fused and they are really frats...Is that possible in your case?

 

I'm sure it's possible, but we're pretty sure that they're identical. The lab that tested the placenta determined as much, and when our neo received the results, he referred to an expert and agreed that they were identical. Maybe I should have made it clear that their eye colors are different shades (one is bright, clear blue and the other is a darker blue/gray), but their hair color is more different (dark brown and strawberry blondish brown). However, like a pp said, they are starting to look more alike.

 

it also could be because babies eye colors don't settle into their "permanent" color for a while, right? (is that a stupid answer?) maybe they are just moving at different paces with that but will end up the same. just a thought.