The outcrossing is a rule for choosing spouse, where marital relationships between members of the same group or kinship system are prohibited. This rule determines that the spouse must be chosen from a clan that is different from his own, prohibiting marriages between relatives.
In today's society, the rule is specifically delimited to prohibit marriages between groups of direct relatives, as in the case of brothers, mother, father; etc. However, in some cultures exogamy is a severe norm that specifies who should be chosen as spouses and marriage with members of the same village, village or tribe is prohibited. In the case of not abiding by the exogamy provision, the punishments range from open disapproval to death.
This implies that in order to get a mate, the members of a certain tribe or community must leave their environment to look for them in a completely different group. The usefulness of this rule is to maintain cooperation between groups, especially in tribes and villages where working together is essential for survival.
There are two types of kinship in society, one is through blood and the other through marriage. In this way, kinship forms a whole structure that, although it is collective in nature, maintains its individuality, spreading its influence around it through the creation of other kinship structures, that is, new families. This kinship network not only has a biological function, but also performs political and economic functions.
It is thought that exogamy may be related to the incest ban rule. However, exogamy prohibits marriage between people of the same group - related or not. Furthermore, the incest prohibition rule is aimed at prohibiting sexual intercourse, while exogamy specifically focuses on prohibiting the marriage bond.
Origin of exogamy
The origin of the rule of exogamy is to favor the union between different social groups and the concept began to be used in the mid-nineteenth century when the first observations of the phenomenon were made in Australian tribes. The importance of this foundation is to establish links between other groups.
The exogamy then began in the political sphere, to strengthen the tribes with alliances with other peoples groups. It is believed that the exogamy started with the capture of women from neighboring tribes to achieve more power over them, or perhaps because of the shortage of women within the same group.
The Belgian anthropologist Claude Levi-Strauss indicated in his works that both exogamy and the law prohibiting incest have a practical focus: forcing women to reproduce with other men from different groups.
The same is true in biology. It is known that the crossing between individuals of a different group or clan is useful to diversify the offspring. A different case is that of inbreeding, which for some authors incest, rather than being a taboo, gives rise to people with hereditary physical and mental problems and transmission of parallel genetic conditions. In this way, it is believed that the oldest societies developed exogamously and not inbreed as was considered in the past.
It is likely that in these societies, while sibling marriage was permitted, it was reserved only for royal families seeking to preserve their lineage for generations to come. But this is not the case with all his people, who did not have this rule to choose their spouse.
In this way, outbreeding corresponds to an adaptive pattern that favors the evolution of the group and avoids the possibility of offspring with genetic problems associated with inbreeding. This not only applies to humans, but to all animals.
The more remote the mixture of individuals, their descendants will be healthier and stronger. Genetic conditions that predispose to the disease are often found in places where inbreeding was common, such as in small communities closed for long periods of time.
However, exogamy not only represents a benefit in the genetic area, but also involves many social and political aspects of different societies and systems.
Exogamy in culture
There are various explanations for exogamy throughout history. Many believe it to be related to totemism, the religious idea of divine respect for clan blood, which is a sacred substance. This is likely to have been one of the motivations of the tribes in seeking spouses in other groups.
However, the exchange of men and women cannot but be considered as a unifying force of different groups, increasing both the economic and political strength of the alliance formed.
Today, outbreeding continues to be practiced in various modern societies and many described in classical literature. It is practiced in some Australian tribes, in Turkish society and the Eskimos. In these human groups, exogamy has remained for several generations, managing to unite different clans in the same blood or language, and with this achieve belonging and sense of a single nation.
There is also a type of exogamy called linguistic exogamy. In this case, the marriage is between two people who speak different languages.
It is very common in the Tukano tribes, indigenous groups in the northwestern part of the Amazon. In these marriages, getting the spouses to speak the same language already makes them members of a nation, gives the sense of belonging and alliance.
In other parts of the world, such as Atlantic Canada, the same phenomenon occurs regularly and families are often made up of one spouse speaking French while the other speaking English.
Exogamy in biology
From a scientific point of view, exogamy is related to the genetic distance between the couple. However, if you look at it from the point of view of ethnic genetic interests, inbreeding allows you to maintain kinship between families, without losing any genes or representative characteristics.
Take for example the case of a Caucasian and Chinese couple. Your children will carry the genes that are most dominant in each parent's case, but about 80% of the other person's genetic conditions will be lost.
In this way we discover that although exogamy does not preserve the pure genetic characteristics of the group where it comes from, what it does allow is to spread the most dominant genes in new areas where the offspring are born.
Looking at it in a simple way, the inbreeding in each genetic combination "shuffles the cards of the gene deck" again, distributing a new combination but with the same elements. Instead, exogamy "scrambles and replaces the deck with a new one" and distributes the new "cards" (genes) to each of the descendants.
Therefore, the interest of exogamy is not the preservation of genetic material throughout the time from generation to generation. His intention is to mix with different people and thus expand an influence that goes beyond a DNA structure.
Exogamy in the world
Although within the explanations of exogamy we even find Darwin's theory of natural selection, where the strongest and best prepared organisms are those that survive (best genetic combinations generated by exogamy); At present, exogamy is interpreted as a survival mechanism, since it reduces conflicts within the clan of origin, with neighboring tribes and establishes a sense of belonging and solidarity between different unrelated individuals.
Exogamy then establishes loyalty and solidifies ties. This promotes social solidarity and cohesion, reducing any internal conflict between communities. In this view of alliances, marriage would be considered a primary and basic form of exchange, like a barter.
In a clan, exogamy reduces the tension of its wives by eliminating competition between them. On the other hand, it allows in a positive way to ensure alliances and stimulate concern and care between different social groups.
Exogamy is a common pattern in societies in Africa and India, where establishing alliances with neighboring clans through exogamy plays a vital role in the survival of their caste and sub-caste system. In this case, a woman in a relevant role within her caste or clan, happens to take another important role in a group other than her own, maintaining the position of the tribe or clan.
In this way, marriage is important to form alliances, transform relationships, provide certain rights and establish legal kinship between the offspring. Marriage alliances are basic to the social structure of primitive cultures, with them a more solid formation is possible, establishing domestic arrangements, transmitting property and political authority.
There are three forms of marriage in the world: endogamy - marriage with people who belong to the same kinship or group; hypogamy; marriage in which the spouse is chosen for similar interests and one of them loses her social position by joining the group of the other; and exogamy- which indicates that the marriage must be made with someone from a clan other than one's own.
Finally, exogamy would be a tool with which groups and clans seek to extend their network in society, develop political alliances, increase kinship and power, sense of belonging and unity in nations, choice of spouse, increase in ties of affections between different tribes, fewer hereditary diseases and adaptive advantages to build ties and strengthen alliances that allow the strengthening and survival of cultures over time.