hmm.. me and a friend just watched a tv program, and in it. it said that twins have the same DNA.. and i thout if they have the same DNA,, and marry two other set of twins..and each has children..
are the children of both set BROTHERS or COUSINS...???
cos from what i kno.. children get the DNA of the mother and father..
p.s. also would the children look the same
2006-12-13 04:58:14 · 9 answers · asked by Anonymous in Science & Mathematics ➔ Biology
didnt kno were to place it.. so i placed it on the biology section.
2006-12-13 05:01:32 · update #1
thanks all great information,,,
2006-12-13 05:20:41 · update #2
I think they would certainly look more similar than normal cousins, but they would not be the same by any means. Each parent has two copies of each chromosome that are not identical to each other. Mixing and matching between these would lead to four possible combinations;
Father: AB Mother: CD Children: AC, AD, BC, BD
4 possible combination for each of the 23 chromosomes would lead to 92 combinations for each child. That would lead to about .01% chance of them being the same if that was the only factor in genetic diversity (which it is not).
In humans, the two chromosome copies also cross over and exchange information during meiosis. Crossing over is a random event that is largely unpredictable and would cause these hypothetical cousins to be no more related than a normal brothers/sisters.
2006-12-13 05:15:56 · answer #1 · answered by baximus_rex 2 · 0⤊ 0⤋
They'd still be cousins, of course, and they would not look the same. Think of it this way: are you exactly identical to your brothers or sisters (assuming you have some)? No. There is always genetic variation between individuals with the exception of identical twins. You have different sperm and different eggs in each twin that combine in unique ways. They would no doubt look very similar but not exactly the same.
2006-12-13 13:09:57 · answer #2 · answered by Sputnik 3 · 0⤊ 0⤋
they would be cousins because the definition is according to relation not genetics. They would look close but probably not the same, because each parent has a set of chromosomes.Each Parent gives only one from each set, so of the 20 some sets the chance that each of the four gave the exact one on all the sets would be really really low
2006-12-13 13:12:04 · answer #3 · answered by smarj4 2 · 1⤊ 0⤋
The children will have a much higher frequency of obtaining a genetic defect due to the simple concepts of inbreeding. Let's say the parents both are heterozygous for a gene and if they have a kid together, the kid has a chance of becoming homozygous defective, leading to severe consequences.
Additionally, assuming the parents have children at say, 18, although the parents are identical and have the same genetic makeup it's more likely that they've been exposed to mutagens (changing their DNA makeup). Mutagens such as sunlight, cigarette smoke, smog, etc. add up and although they may be quite small, they will actually make differences in the DNA of the twins - technically making them no longer 'identical'.
EDIT: Even if the parents are identical, the concept of meiosis (where a random half of one's parental genes is taken up) on top of homologous recombination (where DNA can add variations to itself when producing sperm/eggs) makes it extremely rare for both sets of children to be identical. Thus, they would be cousins and the chances their genetic makeup is identical is incredibly rare.
-Kevin
2006-12-13 13:05:36 · answer #4 · answered by Squawks 3 · 0⤊ 3⤋
They would still be cousins. The kids would look different because they would be getting a random mixture of genes from their parents. Each parent has 2 copies of each chromosome so they have 2 copies of each gene. These 2 copies may be different from each other. During meiosis (the process that makes sperm and eggs), the 2 copies of the chromosomes split apart to make 2 separate cells with just one copy of each chromosome. Which copy of the chromosome ends up in each new cell is completely random. Each kid would get a different set of genes passed on from each parent, so they would be as different as any other set of siblings.
2006-12-13 13:11:37 · answer #5 · answered by Leia V 2 · 1⤊ 0⤋
My mom was telling me about a tv show where there were "identical cousins" because of twins marrying twins, but I don't know of any real-life incidents. Sorry, can't remember the name of the show.
2006-12-13 13:02:19 · answer #6 · answered by staubfinger 4 · 0⤊ 0⤋
They're first cousins -- but, you're right, a DNA test would show them as closely related as brothers and sisters.
...and no they wouldn't look alike. They'd look as much alike as brothers and sisters normally do.
2006-12-13 13:36:44 · answer #7 · answered by Anonymous · 0⤊ 0⤋
They are cousins
2006-12-13 13:05:14 · answer #8 · answered by GD-Fan 6 · 0⤊ 0⤋
genetically, the offspring would be brothers and sisters
politically and maybe pyschologically, they would be cousins
2006-12-13 13:03:25 · answer #9 · answered by hanumistee 7 · 0⤊ 1⤋