Talk:Consanguinity

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I'm gonna try to work on this article in more detail in the coming weeks. Feel free to help. Also, I may change the chart I made. --Doctorcherokee 01:16, 3 Dec 2004 (UTC)

I wrote this:

Consanguinity is measured by degrees of consanguinity, which can be defined in several different ways. The most common definition is the modern civil law definition, which increases by one with each step up or down along the shortest path between two individuals in a family tree; thus, for example, you are one degree from either parent, or from your children; two sibilings are two degrees apart -- one step up to the common parent, another back down to the sibling. This is also the definition used in Roman law.
Degrees of consanguinity defined in this way are directly related to the probability of the two individuals sharing a given gene, where the probability is 2 − n where n is the number of degrees of consanguinity. For this reason, breeding with someone with a close degree of consanguinity carries an elevated risk of genetic problems due to inbreeding.

Now I'm not so sure that this is accurate, so I've taken it out. Does anyone know

  1. the accurate legal situation, for various jurisdictions and religious traditions?
  2. the correct biology and genetic probabilities?

For example, siblings share two direct common ancestors (mother and father): do they get a "double dose" of shared genes, so should n be 1 in this case? What about other more complex cases? -- The Anome 00:27, Feb 1, 2005 (UTC)

Aha. This [1] should shed a bit more light on the subject... -- The Anome 00:29, Feb 1, 2005 (UTC)

OK, I now see that my previous treatment was half-baked, and plain wrong for siblings etc. However, considering the relationship of the various non-genetic schemes to the distance measured by the coefficient of consanguinity, and considering the "background noise" levels of the coefficient of consanguinity in the general population should provide an excellent scientific counterpoint to the religious, legal and historical story of consanguinity. This could be an excellent article! -- The Anome 00:46, Feb 1, 2005 (UTC)


Contents

[edit] Thoughts

It should be noted here that the chart doesn't follow the "intuitive fractions" people often employ when discussing this: siblings equal 100%, parents and children 50%, grandparents 25%. The up a step down a step makes sense for cousins and aunts and uncles (the latter technically 50% if they are 100% to mom or dad) but it doesn't seem right for siblings. If anything they should be ranked zero--as close a genetic match to us as is possible. Marskell 15:29, 29 August 2005 (UTC)

I think that you're right, siblings should not be less related than parents, however, I don't know if they more. -- Kjkolb 09:23, 22 October 2005 (UTC)

[edit] Cousin Chart

  • I think merging the 2 articles is a bad idea. I vote NO. Dr U 07:20, 3 February 2006 (UTC)
  • Merging the two articles is a bad idea because there can be innumerable consanguinity charts; the Cousin Chart is only applicable to consanguinity in the system of English speakers of European ethnicity. To include this chart within the Consanguinity article would invite the inclusion of the countless other consanguinity systems, which has the potential of making the article too bloated. Instead, the Cousin Chart article should perhaps be renamed English Language Consanguinity System, which would allow future articles concerned with other consanguinity systems. I vote NO. Too Old 18:16, 3 February 2006 (UTC)

[edit] Degrees of Consanguinity

I'm pretty sure that the 4th degree of consanguinity is between first, not fourth cousins

Actually it is. Ego -> Parents -> Grandparents -> Aunt/Uncle -> Cousin --Sven Lotz 11:42, 14 July 2007 (UTC)


[I added a pdf. link] "The TABLE of Degrees of CONSANGUINITY and AFFINITY" enacted by Pennsylvania Law in the year 1705, found in "The Legislative Reference Bureau, an agency of the Pennsylvania General Assembly," a publicly available web site: http://www.palrb.us/default.asp

Joe Menkevich - local history researcher in Philadelphia. Bigjoe5216 09:04, 9 October 2007 (UTC)

[edit] Expert attention needed

I came here looking for info on aunts, uncles, nieces, and nephews. Some or all of those words are redirected to the related article Cousin, but that article is very light on covering them. Looking at Cousin and this article and their talk pages, it seems that both articles are pretty weak. I think somebody needs to come in and clean house. Sibling could use a bit of housecleaning, too. Lou Sander 22:06, 9 February 2007 (UTC)


My name Is Dr Michael Black, Curator for www.consang.net on behalf of Consanguinty expert, Prof. Alan Bittles. I have added a paragraph on he genetic definition of Consanguinity and added external links to the Consang.net database. This has recently been made into a wiki and is being updated, with exciting updates planned for the near future. --Dr Michael Black 08:09, 27 April 2007 (UTC)

Presuming that's the section under 'Genetic definition', I have to say that I found it jarringly out-of-place with the tone of the rest of the article, being highly technical and with no definition of its terms. That said, I appreciate the attempt to provide some genetic background to the subject of - literally - mixed blood, where the remainder of the page is legal / cultural in its emphasis.

I do find the article itself rather light on solid information about the subject, and it certainly didn't help me to find the information I wanted: having read (on the Cousin page) about the percentage of consanguinity between first cousins, I simply wanted to know why the percentage given (0.125%) was half what I would naively expect (0.25%). I would really appreciate some (entry-level!) information on how consanguinity is calculated between individuals. This article on GeneWeb was the best I could find on the subject with a quick Google search. CuriousHybrid 16:18, 29 October 2007 (UTC)

[edit] Genetic Disorders

I've added a section on the increased risk of autosomal recessive disorders in consanguinous relationships. --Mike Burden (talk) 11:51, 27 April 2008 (UTC)