I know that fraternal twins share no more genetic material than regular siblings do, but why do some of them look so much alike (like Mary Kate and Ashley Olsen for example)? I have never seen regular siblings that look so much alike.
2007-05-21 15:29:56 · 8 answers · asked by MissM 6 in Science & Mathematics ➔ Biology
Mary Kate and Ashley are not identical. If you do a search on them, all of the sites confirm that they are fraternal.
2007-05-23 16:25:40 · update #1
Mary Kate and Ashley are fraternal twins.
There is a theory about this:
Polar body twinning or Half Identical Twinning:
Polar body twinning, sometimes called half identical twinning, has not been proven to occur in humans. Scientists have speculated that it may occur when an egg (oocyte), before fertilization, has a small cell break off (the polar body). This cell does not function and will usually degenerate and die. It is thought that if the egg is older, the splitting off of the polar body could take place in an abnormal way and become larger, receiving more nourishment. In this case it might not die as it usually does. Instead, it could act as a second egg.
The polar body and the egg would share identical genes from the mother, but could then be fertilized by two separate sperm from the father. This will result in twins who share about 75% of their genes. This could explain why some fraternal twins look as alike as some identicals, but it hasn't been proven that it occurs, or that it would produce viable twins.
2007-05-21 15:52:38 · answer #1 · answered by Barbara 6 · 0⤊ 0⤋
Fraternal Twins That Look Alike
2016-11-14 21:28:26 · answer #2 · answered by mastrolia 4 · 0⤊ 0⤋
The reason is that as siblings they are the same age as well. Most of the time we see siblings several years apart going thru different stages of development so that the differences are accecentuated.
Watch kids grow for a while and you will see the ackward times are almost always then followed by beauty for a while and then back to ackward again. When kids are the same age they get to experience these together.
2007-05-21 15:35:32 · answer #3 · answered by lovingdaddyof2 4 · 0⤊ 0⤋
I'm pretty sure that Mayor McKim is an idiot, Mary-Kate and Ashley are definitely fraternal twins...
2007-05-21 15:34:43 · answer #4 · answered by wahiv4 3 · 2⤊ 0⤋
mary-kate and ashley are identical twins actually...
but some sisters (not twins may look very alike) as do cousins sometimes!!
I look after 2 boys at a daycare centre and thought they were identical twins, not even realising for a day that one was older by a year than the other!!! I still have difficulty!
THere is still a lot of DNA in common between borthers and sitsters and even between cousins too and its just luck that they share more chromosomes in common than other brothers or sisters.
2007-05-21 20:35:02 · answer #5 · answered by mareeclara 7 · 1⤊ 5⤋
Mainly because what they share, they shared at the same time, so you don't have a 9 month or more difference in ages between the individuals.
2007-05-21 15:33:45 · answer #6 · answered by cattbarf 7 · 0⤊ 1⤋
While they may be from seperate eggs they still were fertilized by the same sperm. Most likely they inherited near exact DNA. The DNA is what makes you what you are. A near match of DNA would cause faternal twins to be close to a perfect match.. thus they would look a great deal like each other.
2007-05-21 15:35:45 · answer #7 · answered by J. W. H 5 · 0⤊ 4⤋
I am pretty sure that mary kate and ashley oleson are identical twins.
2007-05-21 15:32:47 · answer #8 · answered by Anonymous · 0⤊ 6⤋