I know it would be almost infinitely unlikely, but wouldn't it be technically possible to have twins that are both identical and fraternal? I.e., they come from different eggs but coincidentally have the same DNA?
2006-06-18 02:48:39 · 9 answers · asked by . 3 in Science & Mathematics ➔ Biology
yes, it is technically possible.
However, as you say, it is almost infinitely unlikely. The chance of fraternal twins being identical would be the same as any two other siblings being identical.
Each parent has a pair of each of the 23 different chromosomes. you will get one of two chromosomes in each set from each of your parents.
If you assume the odds of getting any one of the two chromosomes of each pair from each parent are 50/50 (assume that each chromosome in each pair is different-which should be true unless there was some incest in your family), the odds would be 2^46 to 1 that a sibling happened to get the same 46 chromosomes. that comes to about 1 chance out of 70 trillion. (that is, of being genetically identical).
another way to calculate this is to figure the odds of having two genetically identical eggs from a woman, which is one in 8.4 million, and mulitplying the odds of having two identical sperm from a man, which is also one in 8.4 million, and multiplying these two numbers together-which gives you 1 chance in 70 trillion.
there are other possible factors, such as how each egg was treated (so were some genes turned on or off), astrology, mitochondrial DNA (which should be the same between any siblings so shouldnt be a factor), development in the womb, and others. However, i assume what you were talking about was if they could be genetically identical, which they can, 1 out of 70 trillion times.
the odds of winning the powerball lottery are 70 million to one. so if you played the lottery one time for each time someone had twins, you would win the powerball lottery one million times for each time someone had identical fraternal twins.
the chance of two random sets of parents having identical twins is theoretically possible, but the odds of that are so extremely low, it makes the odds of the lottery or identical fraternal twins look like a near certainty.
2006-06-18 08:58:08 · answer #1 · answered by optionrightio 3 · 0⤊ 0⤋
This is a good question. I see what you are thinking and saying here. It does seem that there could be a possibility. IF, All conditions were correct. The only problem I would see with this is in the Eggs themselves. I am not sure what the role the Egg actually plays here. I will do a little research. BUT, even if the Egg has a role in the DNA, then we could still faced with this question; IF, everything was just right could this happen? Then the only answer would be it is in the Definition of these two words; "Identical Twins" and "Fraternal Twins". Which would mean; Theoretically you are correct, it could happen, BUT, Technically you are wrong because of how people see the Two words to define. Hope you see my point. I do a little looking in case no one gives a Reason, I will!!!
OK, here is the "Scope on the Scoop" Too many variables are involved. Heck, with Identical Twins they may/not share the same Placenta. Depends on the time of Split. Sperm, Eggs, and all kinds of BIG Scientific Words play a Big Role in this. BUT, as "Bozo the Clown" says below me It could be possible, but, the odds are going to be Astronomical. It like two people being born in separate parts of the world at the same exact time (Give or take a few minutes), having different parents, and being Identical DNA Twins. I do want to say, you did ask a really good question, it gets one to thinking, if they want.
2006-06-18 03:03:22 · answer #2 · answered by Snaglefritz 7 · 0⤊ 0⤋
Identical twins are just that-exactly alike. In looks and DNA. Fraternal twins can favor, but they are from two different eggs, they will not share the same DNA. Their DNA will show that they are siblings. There are several sets of twins in our family. Hope this helps.
2006-06-18 04:31:33 · answer #3 · answered by organic gardener 5 · 0⤊ 0⤋
Sorry, but identical; fraternal twins is impossible. If the twin are fraternal, it means that two eggs/sperm were involved so while the DNA can be very similiar, it cannot be identical. You can only get identical twins if one feritlized eggs splits and seperates into two zygotes.
2006-06-18 02:54:43 · answer #4 · answered by DrHue 2 · 0⤊ 0⤋
Only with cloning - which would be by definition the process of making identical twins anyway.
Here is the reason: All eggs are different, and even if there were two identical ones, then your chances of finding 2 identical sperm are insignificant statistically.
2006-06-18 02:52:36 · answer #5 · answered by Zelda Hunter 7 · 0⤊ 0⤋
No its not possible to have the same DNA if they are seperate eggs there will always be that one strand that is different. - the twins will either be identical (same egg, DNA split) or fraternal (seperate egg, seperate DNA).
2006-06-18 02:55:34 · answer #6 · answered by Mintjulip 6 · 0⤊ 0⤋
Impossible.
2006-06-18 02:51:34 · answer #7 · answered by ? 4 · 0⤊ 0⤋
No more than any other two siblings. They just happen to have been conceived at the same time and gestated together. They aren't any more alike than my sister and I, who are two years apart.
2006-06-18 02:52:55 · answer #8 · answered by MOM KNOWS EVERYTHING 7 · 0⤊ 0⤋
It's possible but the odds of it occurring are astronomical. Bet on the lottery first.
2006-06-18 03:04:50 · answer #9 · answered by Bullwinkle Moose 6 · 0⤊ 0⤋