If a two identical twins have a child with two identical twins, are the offspring identical twins?

Question

If two identical twins have a child with two identical twins, are the offspring identical twins?

See item number 7.

http://www.oddee.com/item_96463.aspx

Answer 1

No, the offspring are not identical twins. As you know, identical twins are created when a fertilized egg - in its early stages, also known as a blastocyst - splits in two. A blastocyst is the original fertilized egg that has undergone mitosis and divided into more IDENTICAL cells. Therefore, if the blastocyst splits into two, the cells that continue to divide in each blastocyst are all IDENTICAL. The blastocysts grow into two separate babies and are identical twins.

However, as you may or may not know, every single egg or sperm the identical twin makes when they are older is different. That is why two children, from the same parents, are not identical. Each person has two "alleles" for every trait they have, and there is always a dominant allele and a recessive allele. I'll try to simplify this. Let's say the trait is eye colour, and the only options in the world are brown and blue. Brown is the dominant allele and blue is the recessive one, which is true and which is why blue eyes are more rare than brown eyes. Recessive alleles become traits ONLY when there are two present - dominant alleles become traits if at least one is present. So if a person has blue eyes, they can only pass on a blue-eyed recessive allele because they must have two blue-eyed recessive alleles to have blue eyes themselves. A person with brown eyes, however, may have two brown-eyed dominant alleles OR one brown-eyed dominant allele and one blue-eyed recessive allele. Either way, they will have two brown eyes, BUT the person with one blue-eyed allele and one brown-eyed allele can make a child with blue eyes. That's the main idea, anyways. Some sperm will carry the blue-eyed recessive allele, and some will carry the brown-eyed dominant allele.

So, in short, even identical twins could have a lot of unseen recessive alleles that change in their offspring. No two sperm are the same, just as no two eggs are the same, so the offspring of two sets of identical twins do not have to be the same. I mean, TECHNICALLY they COULD be, but the chances are so astronomical that you would waste your time thinking about it.

However, the children may look something alike - just as any two children from the SAME parents could look alike.

Hope my eleventh-grade biology helped! (:

Answer 2

No. They may be similar but not identical. How many brothers do you know that are a year apart in age but look exactly the same? Those brothers share the exact same DNA from their parents but they, more often than not, look totally different.

Answer 3

No, because each time you get pregnant, there are a billion different combinations of genes depending on the egg and the sperm.  The cousins will probably look very much alike, more like siblings.  

Answer 4

Nope.  They are double cousins.  They will probably look very similiar if they're of the same s*x.

Answer 5

to a layed understanding of genetics.. this is a very deep question

but as said, random assortment of the genes would result in different, if not similar offspring