help/ DNA/blood type questions?

Question

Can you answer these questions?
Explain the process of how our DNA is transmitted to our offspring (in detail).
Do siblings have the same DNA? Explain your answer.
Why are some traits more common in a certain gender?
How are identical and fraternal twins alike/different genetically?
What are the dominant and recessive alleles that are responsible for blood type?
What are the parental genotypes needed to produce a child with O blood? A? B? AB?

Answer 1

Explain the process of how our DNA is transmitted to our offspring (in detail).

Every normal human cell has two of each DNA strand. The reproductive cells, however, have only one of each DNA strand (half as many strands as the rest of the cells in the human body). In this way, the offspring receives half a set of DNA from the mother and half a set from the father, thereby getting a full set of DNA. Since two of each strand of DNA exist, and only one is found in the reproductive cell, the strand is randomly chosen from the two. In this way, the reproductive cell has a random subset of the parent's DNA, having one of each strand instead of two.

Do siblings have the same DNA? Explain your answer.

Siblings generally have some of the same DNA, but their DNA is not identical (unless they are identical twins). Because they both inherit their DNA from their parents, they will probably get some of the same DNA. However, since each parent has two of each strand and contributes only one, this randomization ensures that siblings will probably not have exactly the same DNA.

Why are some traits more common in a certain gender?

Some traits are more common in a certain gender because they are carried on the X chromosome. Such traits are called "sex-linked". They are caused by recessive genes located on the X chromosome; the recessive gene will cause the abnormality if expressed, however, the presence of a "good" gene will suppress the trait. Since a female has two X chromosomes, she has twice the chance of getting a "good" gene, and is much less likely to have the abnormal trait. Males have only one X chromosome, so if a man has the recessive gene, he will always have the abnormal trait. A woman who has one "bad" gene and one "good" gene is called a carrier: if she marries a normal male, her male offspring have a 50% chance of receiving the trait, and her female offspring have a 50% chance of being carriers themselves. If she marries a male who has that trait himself, her male offspring will have a 50% chance of receiving the trait, and her female offspring will be 50% carriers and 50% having the trait themselves.

How are identical and fraternal twins alike/different genetically?

Identical twins have exactly the same DNA, similar to clones. Fraternal twins are no more genetically similar than any siblings would be... they both receive "family DNA", but they do not have exactly the same DNA.

For the blood type questions, I refer you to the following page. It should answer your questions better than I probably can:
http://en.wikipedia.org/wiki/Blood_type

Answer 2

identical twins have the same DNA, fraternal twins do not since they are from 2 different eggs and not one that split in 2. Siblings have similar DNA but not the same, they get different traits and things of that sort from the different sperm/egg they came from. hope that helped with your homework... try reading the book next time

Answer 3

Quick answers; you research the rest.

Meiosis.
Siblings do not have same DNA because meiosis schuffles the DNA around.
Because they are sex-linked genes - coming from sex chromosome.
identical twins crom from same egg while fraternal twins come from two seperate eggs (i think?)
Uhh...Rh factor? not sure on this one
O - AB neg, A, b neg, b A neg, AB positive

Answer 4

To add to the blood typing response:

blood groups are determined by allele expression. Someone who's blood type is AB will have I(superscript A) I(superscript B); A will have I(superscript A) I; O will have I I.

From Mendelian genetics, you should be able to figure out your own question.

Answer 5

Identical twins are from the same egg and sperm. The egg splits forming two fetus'. There for their DNA are identical as well.

Fraternal twins are from seperate eggs and seperate sperm. There for their DNA is the same as any sibling.
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Answer 6

Somebody has a term paper or a test and didn't study!