It’s like Webster says.
The practice of marriage within a social group. Examples of such a group
include occupation, family, colour, caste, nationality and religion. Religion is
probably the most relevant grouping worldwide. The Amish community and Orthodox
Jews may be the most famous practitioners but endogamy, to varying
degrees, is extremely common.
Endogamy encourages group
cohesion and the continuity of group cultural practices. In some contexts it
may have important socio-economic underpinnings. In agrarian or pastoral
societies for example, marriage within a group ensures group ownership of land
or animals over generations. Indeed in some societies, exogamy (i.e. marriage outside the group) is strongly discouraged and may be punishable - by social exclusion, violence or otherwise.
In small groups, the
practice of endogamy often (but not necessarily) entails consanguineous marriage. This is usually
defined as marriage between two second cousins or closer relations. Genetic
inbreeding has the well-known unfortunate consequence of concentrating
recessive alleles. Groups practising strict endogamy therefore commonly suffer
a high burden of inherited disease. Mother Nature it seems, doesn't approve.
Perhaps you are bored. Let
us sing.
The Endogamy Song
(Let’s Keep The Good Genes In)
Scene : A Monastery garden. A Monk is carefully examining
a row of bean plants. Enter Parents and Errant Son, deep in discussion. Fingers
and tongues are wagging. Gradually, the Parents begin to sing and
the Beans begin to dance.
Well there once was a Monk named something or
another
While growing peas he was amazed to discover
That the traits of the beans
Were transmitt-ed in genes
Let’s keep the good genes in!
As with beans well so with people –
Genes they are our stalk and steeple
Your father’s nose and your mother’s wits
And your grandma’s pains and your uncle’s fits
They’re all right there in the Book o’ Doom
That is writ by the Maker in your Momma’s womb!
Let’s keep the good genes in!
Our kids will have our Re-li-gious Culture
Our tribe will not be left to vultures
It’s our ge-ne-tic pick ‘n mix
Not your fre-ne-tic teen antics {The
Monk frowns suspiciously}
That will decide who marries who!
Let’s keep the good memes in!
The priests and the laity are quite agreed
That the trees we plant must be of noble seed
Our councils ecumenical
Preach the crypto-eugenical:
Let’s keep the good genes in!
If you run off and marry some tart
You’ll dilute our stock and you’ll break our hearts
Mix Robinson’s and Ri-be-na?! {The Monk shakes his head sadly}
Mix Lion and Hy-e-na?! {The
beans look appalled and wail}
Let’s keep the good genes in!
We’ll find you a nice girl, someone you like
Would you look at this one here, boy, what a sight!
She got hips that launched a thousand ships
Of hopeful in-law’s fishing trips
She’s a respectable bespectacled genetical receptacle
She’ll keep a tidy home!
She prays, she cooks every del-ect-able
You got no cause to moan!
Let’s keep the good genes in!
Well Mummy and Da-ddy I see what ya mean
About the birds and the bees and the peas and the genes
If it’s really so imperative
I’ll find a foxy relative…
We’ll keep the good genes in!
{The Beans, the Parents, the Monk and the Errant Son join
hands and dance joyfully into a whirligig. Camera fades.}
- Modell, B and Darr, A. Genetic Counselling and Customary Consanguineous Marriage. Nature Reviews Genetics 3, 225-229 (March 2002)