- #1
benhou
- 123
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This question started with the asian culture where cousins on the father's side is "closer" than cousins on the mother's side.
If we have three siblings, brother 1, brother 2 and sister. let's say, b1, b2 and s3. They each have one child, c1, c2 and c3. The asian culture would be that c1 is more closely related to c2 than c3.
How i understood it was, b1, b2 and s3 each has inherited half from their mother and half from their father, let's say m and f; c1, c2 and c3 has inherited half from b1, b2, and s3 respectively, then each of c1, c2 and c3 (the grandchildren) has 1/4 of the DNA from each of m and f (the grandparents). Therefore, c1, c2, and c3 should be genetically related to each other at the same degree.
However, after i reviewed meiosis i remembered that chromosomes come in pairs and they undergo recombination before the cells split. Let's say s3 actually has two children, c3 and c4. c3 has inherited all the 1 genes from mom, and all the 1 genes from dad, but c4 inherited all the 2 genes from each parent, all of a sudden we have siblings that are opposite to identical twins. While that could happen, the cousins only need to have inherited one single common gene from the grandparents to be more genetically related to the siblings. Likewise, the cousins c1 and c3 can be more genetically related than c1 and c2.
Am i right about the siblings and cousins? Please comment and educate.
If we have three siblings, brother 1, brother 2 and sister. let's say, b1, b2 and s3. They each have one child, c1, c2 and c3. The asian culture would be that c1 is more closely related to c2 than c3.
How i understood it was, b1, b2 and s3 each has inherited half from their mother and half from their father, let's say m and f; c1, c2 and c3 has inherited half from b1, b2, and s3 respectively, then each of c1, c2 and c3 (the grandchildren) has 1/4 of the DNA from each of m and f (the grandparents). Therefore, c1, c2, and c3 should be genetically related to each other at the same degree.
However, after i reviewed meiosis i remembered that chromosomes come in pairs and they undergo recombination before the cells split. Let's say s3 actually has two children, c3 and c4. c3 has inherited all the 1 genes from mom, and all the 1 genes from dad, but c4 inherited all the 2 genes from each parent, all of a sudden we have siblings that are opposite to identical twins. While that could happen, the cousins only need to have inherited one single common gene from the grandparents to be more genetically related to the siblings. Likewise, the cousins c1 and c3 can be more genetically related than c1 and c2.
Am i right about the siblings and cousins? Please comment and educate.