Q. about siblings reproducing together...?

Question

As morally wrong as it is for human relatives to have sex/reproduce with one another, why is it a bad idea in physiological terms, in particular brother and sister relations?

Does it have something to do with them both sharing the same DNA etc? I've heard of possible physical deformaties and mental problems e.g. retardation etc..

Do any other species have these problems, like say feral cats who tend to cluster in groups and produce many offspring that live together?

And no, for you sicko's im not thinking about doing any of the sort.. I'm just wondering.

Thanks!

David G, and Evitta - f#ck off. Yeah, my bipolar, that's what made me ask the question. Ner, we're in a "QUESTION" forum.

Answer 1

The problem with reproduction between close relatives is the tendency for harmful recessive genes to be expressed.

When reproduction occurs within a large population of unrelated people, any given recessive quality that is rare will almost always fail to be expressed, because the person with the recessive gene will mate with someone who lacks it (since the gene is rare), and instead has a dominant gene that is not harmful and is expressed instead.

However, two people who are closely related, especially parent and child or siblings, are likely to have the same recessive genes in common. Even if the gene is rare in the general population, if you do have it then the odds of sharing it with your mate suddenly become 1/2 if the mate is your parent or sibling. These odds become lower when the relative is more distant, like a cousin, but remain higher than in the general population.

If you reproduce with your own sibling, problems emerge very rapidly; the Pharaohs of Egypt almost always married their own sisters, and the birth defects were devastating and widespread. When a group frequently marries within itself, problems emerge more slowly as the members of the group become more gradually related to each other; the larger the group, the more slowly, less widespread, and less severe the effects are. This is the cause of haemophilia among the European royal families (which are all related to each other), maple syrup urine disease and Crigler-Najjar syndrome among Mennonites, and Tay-Sachs disease among Ashkenazi Jews and other groups. When it occurs in a large populations (such as Mennonites or Jews), it is referred to as a genetic bottleneck. When it occurs within a family (even a very large one like the European royals), it is called inbreeding.

Answer 2

First of all it does happen in cats, dogs, and most other animals. Take for example any pure bred dog. They are inbred to keep certain characteristics in the bloodline.
The danger of reproducing with a sibling or other close family member (cousin) is that you share much of the same genetic make-up. This allows recessive genetics traits, which would be masked by a dominant trait from some other gene pool, to be expressed. This can lead to genetic abnormalities which can cause retardation, physical deformities, etc.
This happens frequently in the Jewish population, because strict Jews will only marry other Jews. This lessens the gene pool and disease like Tay Sach's disease (a genetic disease) to be spread and abundant in the Jewish population.
Hope this helps!

Answer 3

If you want to deal with the moral aspect of doing this, that's a question for the religion and spirituality section of Yahoo Answers. As for a biological explanation, the reason is simple: close relatives have similar DNA. Genetic variety is beneficial (and the whole purpose of sexual reproduction), so reproducing with a sibling would result in a child nearly identical to the parents. Also, lack of variation can cause genetic diseases because relatives are more likely to share rare recessive alleles. The monarchs of Europe, for instance, intermarried often, causing many of them to develop hemophilia.

Answer 4

Mainly because if both of them have a "fatal" genetic predisposition, say to being a hemophiliac or Downs syndrome, even if it is recessive in both parents, the chances are EXTREMELY high that all offspring will get both the gene and the morbid disease. Thats why most animals have such strong prohibitions on inbeeding.

Answer 5

Yea, well this is what farmers and ranchers used to do with livestock. They tried to produce all the good characteristics, but with the genetic similarity, the recessive traits will show. Some of those are fatal. So yes, it is bad to have a kid with a biological relative. not bad for you, but for the kid. And people who don't have a clue what this is about please refrain from answering here.

Answer 6

Visit Tasmania. All your questions will be answered :P

Answer 7

You're Bipolar.........A Mental Problem..............
Hmmm..........Do Your Parents Look Alike??
Just Wondering...............

Answer 8

hell of a thing to just wonder dont you think . your secrets out girl .