part 6 G4BB: Double or Nothing

Double or Nothing

6.1 WARNING: This could be the last chapter of G4BB you may read! Not because I won’t be writing any more…are you kidding? I’m just getting warmed up! No, it’s because today we’re going to be getting to some real nitty gritty…real meat-and-potatoes time. You may find it fascinating…real now-that’s-what-I’m-talking-about! stuff. Or you may throw up your hands in resignation. I admit some of the discussions and charts up to this point have been confusing…only because they’re by nature complicated…nothing can be done about that. In future chapters I’ll be re-examining and elaborating on many of the topics, definitions, and relationships mentioned. But remember when I said that Family Trees can get repetitious, in terms of their general structure…unless something unusual comes along? Well, today, with cousins, it does…

6.2 But before the meat, some potatoes. Three types of relationships are often confused: half, step-, and in-law (or by marriage.) The crucial thing to remember is that half- relations are blood relations…the other 2 are not. The other 2 exist because of a marriage…step- thru the marriage of your parent…-in-law thru your own marriage. And because these relationships come into being thru a marriage, it is an interesting question whether these relationships disappear when the marriage is dissolved.

6.3 In-laws are the blood relatives of your spouse…which of them you consider “related” to you is a matter of personal preference combined with social convention. For example, a man might say that his wife’s cousins are his cousins, by reason of their being his cousins-in-law. Or he might say he has no relationship to them at all. And his wife might see it just the opposite! It can become a matter of law with regard to inheritance, and also with eligibility to marry…both secular and religious laws deal with these issues in various ways, thru-out history, and around the world today.

6.4 Similarly with step-relations, which are blood relatives of a new spouse of your parent. They exist in legal contexts, but also personal ones…a man might say: “Even if your Mother and I get divorced, I’ll always consider you my Step-Son.” Or even “my Son.” Here’s an example: Researching the history of the Bakers Chocolate Company, I found that in 1883, the owner of the firm was described as “the fourth-generation familial owner,” altho he was the “step-nephew” of the previous generation’s owner. I took this to mean he was the son of the previous owner’s step-brother…and it’s interesting that in this case they considered that to be “keeping it in the family.” Technically speaking, I’m not sure I would have, but that’s my point.

6.5 Another relationship you might encounter is that of foster-. Now in the US today, the term signifies a guardian relationship between adult and child, without a formal adoption. In days gone by, the term was used more generally to describe the adults who raised you…they could be your relatives, such as your Grandparents, Aunts and Uncles, or older Siblings…or no relation at all.  For example, in legend, King Arthur was raised by a knight named Ector, whom he considered his Foster-Father. Ector’s Son Kay was Arthur’s Foster-Brother…and presumably he had Foster-Cousins as well.

6.6 I’ll mention 2 other types of cousins which for us are mainly the purview of anthropologists, but have real meaning to real families in other societies, past and present. These are parallel cousins and cross cousins. The definitions are simple: your parallel  cousins are the children of your Father’s Brothers or your Mother’s Sisters, Your cross cousins are the children of your Father’s Sisters or your Mother’s Brothers. Parallel, from siblings of the same gender as your parent…cross, from siblings of the opposite gender as your parent.

6.7 You might well wonder what difference it could possibility make? The answer is this: suppose a society allowed 1st Cousins to marry each other, but not Half Siblings. They might then forbid the marriage of parallel cousins, but allow the marriage of cross cousins. The thought was, if 2 Brothers had sons, these sons might not be 1st Cousins, but might be Half Siblings, if one of the Brothers had relations with his Sister-in-law. Same with 2 Sisters…the problem was, you alway knew who a child’s Mother was…but the identity of the Father could come into question. Now with cross cousins, you knew the 2 Mothers are not related…so for the 1st Cousins to be actually Half Siblings, Brother-Sister incest would have had to occur…and this was considered less likely than hanky-panky between in-laws. Thus cross cousins could marry, parallel cousins could not. What can I say…before DNA testing, that’s how these things were handled…

6.8 So much for the potatoes…now for some meat: Half Cousins and Double Cousins. But first, I need to introduce a type of family tree format that is a bit different from what you may be familiar with, and I’ll demonstrate it with 1st Cousins Abner and Zeke. In Chart 7-A, we have a typical family tree diagram…you can see that Abner’s Father and Zeke’s Father are Brothers, so Abner and Zeke are 1st Cousins. This is considered a unilineal relationship, that is, thru just one side of the family…notice that Abner’s Mother and Zeke’s Mother are not related. But if they were somehow related,we’d have a bilineal relationship, and the Mothers’ family would have to be  on both sides of the diagram…such redundancy would cause much confusion. Therefore, we use what I call a Parental Tree, Chart 7-B. In this format, Abner, Zeke, and anyone else whose parentage is relevant to their relationship has 2 lines connecting them to 2 parents, a Mother and a Father.

6.9 And I should mention that Chart 7-B is itself a hybrid between the 2 kinds of charts, since Abner and Zeke’s Fathers are connected to their parents by only 1 line…this is a simplification on my part, which I will use where convenient. The correct Parental Tree is seen in Chart 7-C. You’ll also notice that in Chart 7-A, the typical family tree arrangement, the “X” represents a marriage, the children of which are connected by a line. Well, it could be parentage without a marriage, obviously…the “X” could represent either. Thus with the Parental Tree, it isn’t necessary…we only need to know whose Mother and Father is whose, and we can reckon all kinship from there, whether thru wedlock or otherwise.

6.10 Half Cousins are the children of your Father’s Half-Brother. And for the time being, we’re talking about Half 1st Cousins. In Chart 7-A, Abner and Zeke were Full 1st Cousins…Abner’s Father and Zeke’s Father had the same parents, the Grandparents of Abner and Zeke. In Chart 8-A, Abner’s Father and Zeke’s Father have the same Father, but different Mothers. Thus, on their Father’s side, Abner and Zeke share only 1 Grandparent, not 2. Notice the awkward “double X” connecting that Grandfather to his 2 wives…the Parental Tree Chart 8-B eliminates the need for the Grandfather to be “in 2 places at once” in the tree.  Abner’s Father and Zeke’s Father are now simply shown connected to the same Father, and different Mothers. Abner and Zeke have the same Grandfather and different Grandmothers.

6.11 Double 1st Cousins are unusual, but not unheard of…perhaps you have such a situation in your own family. Simply put, 2 Brothers will usually marry women who are unrelated to each other, as shown in Chart 7. But if the 2 women they marry are related to each other, additional relationships between their offspring result. Chart 9 shows 2 Brothers who married 2 Sisters…Abner and Zeke are 1st Cousins on both sides of their family, and are thus Double 1st Cousins. The first reaction I often hear when discussing this is: Is that legal? Setting aside the fact that in most of the world today, and in half the states in the US, 1st Cousin marriages are legal, that’s not what’s happening here. No blood relatives have married each other. Yes, Zeke’s Father has married his Brother’s Sister-in-law, but short of religious prohibitions, this is completely legal, and at least in our society, completely proper. And remember, when populations were a lot less mobile than they are today, it was much more likely to happen thru sheer circumstance.

6.12 Now unless you have this in your own family, Double 1st Cousins present some unique features that probably never occurred to you. For example, most people have 2 unrelated sets of 1st Cousins, those on their Father’s side and those on their Mother’s. Double 1st Cousins have just one set. Likewise “Single” 1st Cousins have 1 pair of Grandparents they share, and each has another pair they do not share. Double 1st Cousins share both pairs of Grandparents…there are no “other” Grandparents.

6.13 And here’s the important part: Double 1st Cousins are more closely related than Single 1st Cousins. This is a good time to introduce the concept of “Coefficient of Relationship” (CR). This is a number that tells how closely 2 people are related. We have a sense, I think, that Full Siblings are more closely related than Half Siblings, and 1st Cousins even less, but beyond that, what? Are you more closely related to your Father or your Brother? Are you more closely related to your Grandmother or your Aunt? What about 2nd Cousins, 1st Cousins once removed, etc.

6.14 The CR of 2 relatives tells how many genes, on average, they have in common. If you remember your high school biology, you’ll recall you get half your genes from your Father and half from your Mother. So the CR between a child and parent is 50%, more generally stated as 1/2. Mind you, this is an approximation: you have 20,000 genes, and its unlikely you’ll get exactly half from each parent, but it’s very close to half, too close to make any real difference.

6.15 The method of determining CR, especially in unusually complicated family trees, can be tricky, but for now I’ll just mention several common ones: Siblings 1/2, Half Siblings 1/4, 1st Cousins 1/8, 2nd Cousins 1/32, 3rd Cousins 1/128, Uncle/Nephew 1/4, Grandparent/Grandchild 1/4. But the most important rule about CRs is that they are additive. This means that if 2 people are related to each other in more than one way, or through more than one family line, their CR is the sum of the CRs for each relationship. Thus, for Double 1st Cousins, the CR is 1/4 + 1/4 = 1/2. In other words, Double 1st Cousins are as closely related as Half Siblings.

6.16 And 3 cheers for North Carolina! All states prohibit the marriage of Half Siblings, but of the states that allow 1st Cousins Marriages, only North Carolina recognizes that Double 1st Cousins are as closely related as Half Siblings, and thus only North Carolina excludes Double 1st Cousin marriages. Whether or not you agree with the law, at they got the math right.

6.17 Now comes the part you’re going to either really love or really hate. Chart 9 shows the ONLY way 2 individuals can be Double First Cousins. But with more distant cousins, it gets more complicated. I’m not going to discuss that very much today, just present the charts and let you ponder them…really, that’s the best way to get an understanding of these relationships…work thru the charts…heck, at the same time, you can be checking to see if I got them right! Charts 10-A and 10-B show both the typical family tree and the Parental Tree for 2nd Cousins. Compare 10-B with 7-B and you can very clearly see where you get 2nd Cousins…in 7-B, Abner and Zeke’s Father’s are Brothers. In 10-B, their Fathers are 1st Cousins and their Grandfathers are Brothers.

6.18 Charts 11 and 12 show the 2 ways Abner and Zeke can be Double 2nd Cousins. Both ways their CR is the same, 1/32 + 1/32 = 1/16. The subtitles of these 2 charts pretty much spells it out: the Bi in Bilineal means they are Double 2nd Cousins owing to their Fathers being 1st Cousins and their Mothers also being 1st Cousins…Abner and Zeke’s relationship comes thru 2 lines. The Uni in Unilineal means their Fathers are themselves Double 1st Cousins…the relationship comes thru just 1 line. And after you’ve pondered for a while, here’s a quiz to see if you’re getting it…sketch out a Parental Chart showing the relationship between Double Half 1st Cousins. Answer next week…see ya!

UPDATE!!! Bilineal and Unilineal Double 2nd Cousins might be termed “regular”…because there is a 3rd “irregular” type…see here: G4BB 70

Copyright © 2011 Mark John Astolfi, All Rights Reserved

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