Consanguineous Marriage: A Curse upon Zhu-and-Chen Village in Chinese History
Bai Juyi (772-846), a renowned Chinese Poet in Tang Dynasty (618-907), wrote a long poem tided Zhu-and-Chen Village. It sings high praises of a village that was completely isolated 6:ore the outside world. According to this poem, this village was situated in Fengxian county Xuzhou prefecttue, Jiangsu province, and there were only the Zhu and the Chen clans, who were content to from generation to generation, marry only amongst each other and bear children that continued the tradition.
Below is the beaming portion of this poem:
In the age-old Fengxian county,
One hundred li from the county seat,
Sprawls a village called Zhu-and-Chen,
Where mulberry trees and hemp plants flourish,
Loom shuttles are heard busy working,
Cattle and donkeys wind over the lea,
Girls fetch water from the clear spring
And boys cut firewood in the hills
No official cares to come to interfere,
And folks are honest and unaffected,
Men don’t leave home to do business,
Nor do they go to serve in the military
Families just manage their village property
Until thy are grey-haired and die.
Alive,they are the village dwellers,
Dead, the village earth.
when old and young meet in the fields,
How happy they are!
Marriages are arranged between the two clans
From generation to generation.
Kin and kith hue together
While young and old from their own bond
Feasts are held every ten days or so
Featuring chicken and wine.
Alive, they won’t part and go far
Lads and maidens spousing their neighbors,
Dead, they are buried around the village.
Contented with their mode of life
They never feel suffering in body and mind.
Thereby many live to their grand age
Blessed to see their great grand children.
Several generations after this poem was published scholars traveled to the remote village, including the famous Song Dynasty poet So Dongpo(1037-1101), not because the world under BaiJuyi’s pen was inviting or idyllic, but because the marriage custom was a curiosity resulting in “Zhu-and-Chen’ became synonymous with an idyllic marriage. Today marriage roles are regarded with new concepts and perspectives, which question if the Zhu-and-Chen Village kin marriages were truly desirable or happy The convention of “kin and kin”, or consanguineous marriage, or marriages to those that share since ancestors in the vocabulary of genetics creates immense threats.
According to genetics, consanguineous unions,or inbreeding, brings tremendous harm to their of spring via hereditary diseases. It has been proven that there are many people who, without betraying any symptoms are potential carriers of genes of recessive hereditary disease.A couple sharing the same ancestry may have the same disease genes as their offspring may inherit identical copies of one or more detrimental recessive genes. These inactive genes are then activated in the offspring, who will inherit hereditary disorders.Statistics reveal that the mortality rate of inbred children is tree times higher than that of children of non-consanguineous couples, and that the incidence of hereditary diseases, such as albinism, congenital deafness,cerebella malformations, hydrocephalus, spina bifida,anencephaly schizophrenia, congenital heart disease, and epilepsy is 150 times higher.
Therefore, the blissful scene in Bai Juyi’s poem that “many live to their grand age/Blessed to see their great grand children” is only an unwarranted, idealized image, as reality was just the opposite.
As previously mentioned, the Song Dynasty poet Su Dongpo initially echoed Bai Juyi’s praise for these distinct marriage customs, but when he became governor in Xuzhou, as part of his efforts to encourage farmers and their work he traveled to that much acclaimed village, which to his dismay had fallen beyond repair and was a disheartening sight. In a mere span of200 years between Bai Juyi and Su Dongpo, the once vibrant village fell into ruin. Though there is no record of the exact reason for the village’s fall, inbreeding is presumed to be the primary cause.
What happens in human society is also true in the world of animals. For instance pug dogs,a Chinese breed of dogs that can be traced back to the time of Confucius 700BC. They were med as royal pets in the Chinese imperial courts and were mated among themselves during that time to maintain purity in the bloodline Unfortunately d1e long history of inbreeding has caused this pug to be more prone to a variety of genetic health problems, and often require more veterinary care than other dog species.
Genetic Inbreeding in the Realm of Giant Pandas
Nowadays, many species on the earth are threatened, vulnerable, endangered, or on the verge of extinction due to man’s ruthless and reckless activities. Their population numbers are so small that their breeding tragically mirrors that of the Zhu-and-Chen village.Giant pandas presently serve as an illustration and reminder of this problem,due to the great difficulties that surround their breeding and reproduction.
The 3rd National Giant Panda Census in 1999-2003 revealed that there were only approximately 1,596 giant pandas in the wild, a warning to the internal community. Compounding the due is that due to human encroachment such as deforestation, highways, railways, power plants, and polluting their integral habitat has been severely fragmented into isolated pocket. Confined within these narrow ranges,giant panda population numbers vary from only a few individuals to one hundred] with no opportunity to integrate, breed or communicate with alternative populations, leaving them with no choice but to mate with those that are their kin] mirroring the case of Zhu-and-Chen villagers. Their mating plight substantially deceases genetic diversity adding to their already fragile vulnerability. Experts have stated that in some secluded locations where the population numbers less than 10 individuals] this species will probably become extinct within the next two or three generations. The glaring fact is destructive human activities has reduced giant pandas to such an impossible situation, that solutions need to be found quickly and upheld.
China has implemented a policy of in-situ and ex-situ conservation. Ex-situ conservation means that some giant pandas are bred and protected in captivity where they are well-fed and sheltered from predators, illnesses and bad weather and thus their survival rate improved. Many years’ experience has shown that ex-situ conservation is one of the effective strategies in the endeavor of giant panda conservation.
Thanks to the devotion and dedication of scientists, presently more than 300 giant pandas have been bred in conservation institutes and zoological parks across China, over 200 in two major institutes,the rest at different zoos. Although such joint efforts should be praised, unfortunately several of these pandas are the outcome of inbreeding, similar to the residents of Zhu-and-Chen village.
Giant pandas as well as many other species are bore with instincts and social behaviors to avoid inbreeding. Biologists have found by studying animals’ behavior that the more remote the genes are between a male and the female giant panda, there is an increase in attraction and mating preferences. If a giant panda is indifferent to the other’s estrous behaviors or if the two giant rather than cultivate intimacy it is probable that one of them detects their genes in the other or that they know that the potential mate is kin. The rejection of potential mates from the same lineage characterize their consideration for their offspring; they choose to mate with the strongest, and those genetically remote,to maintain diversity and preserve the quality of their descendants, a genetic strategy that has been developed in evolution over eight million years.
As giant panda population numbers have become small, fragmented and unstable, they have been left with very little options regarding mating partners, thus to conserve and maintain this iconic species, help is needed Thus the breeding and reproduction of giant pandas is a main concern for scientists, especially for those giant pandas living in captivity.
Current Solution: Optimized Mating in Captivity
The lessons from the Zhu-and-Chen village and the giant pandas’ genetic strategy have led scientists to be cautious in their conservation practices.They need to enhance the scientific mating strategy of giant pandas to ensure future generations will prosper and be healthy Previously a traditional approach was utilized, but currently a more sophisticated approach is being employed.
traditional approach: Remote Lineage Mating
This is the safest approach.Wild giant pandas in China populate a region that resembles a stripe shape, about 1,000km, defined by Qinling Mountains in the north and Daliang Mountains and Xiaoliang Mountains in the south.
As a result of topography and human encroachment,the giant pandas territorial range is split up into many lone pockets. As giant panda conservation began in China, giant pandas were all from these unconnected communities, either solicited from captive breeding bases in their natural habitats, or randomly captured in the wild, or rescued. When scientists paired them for breeding they saw to it that the male and the female were from different nature reserves, as in theory, the further the location of their birth coincides with an increase of genetic diversity and thus minimizing the possibility of the offspring will inherit healthy diseases.
A case in point is Mei Mei, a legendary giant panda mother in the Chengdu Zoo and the Chengdu Research Base of Giant Panda Breeding in 1980s and 1990s.
Mei Mei’s story begins with her birth within Dafengding Nature Reserve, which lies inside the Daliang Mountains. This nature reserve is located at the southern tip of giant panda habitat,and is highly isolated from other locations. Due to this the giant pandas in this region are thought to be of an independent lineage. Experts decided that Mei Mei was unrelated to those in other nature reserves in terms of consanguinity.
In 1975 Mei Mei was Found starving and ill in the wild, therefore she was brought to the Chengdu Zoo to receive medical care. From the 19805 on-wards she mated with males from different nature reserves at the zoo and the panda base. Owing to distant genetic diversity the mating was natural, with no human intervention. Up to 1992, Mei Mei had given birth to nine liners of eleven cubs, of which seven survived. Hardly any other panda mother can compare with her. She became the icon of Chengdu in those years, and her story was made into a documentary called “Mei Mei’s Family”.
Sophisticated Approach: Applying Genetic Technology To Breeding
when the giant panda mating season arrives for those in captivity in spring, the strategy of remote lineage mating no longer works, as it is difficult to track down their genetic ancestry The difficulty is due to the practice to first have an estrous female in a zoo or at the panda base mate .With several males naturally, and then be artificially inseminated to strengthen the possibility of offspring, making dearly identifying the father of the cub(s) nearly impossible. To solve this problem molecular biology and bio-engineering came to the rescue in the form of paternity testing.
Last century countless scientists were seeking for a hereditary code of life, and their findings revealed that genes code are hidden in cells, called chromosomes, which contain the entire instructions for producing and maintaining life, termed deoxyri-bonudeic acid (DNA).
DNA has played an important role in various disciplines such as criminal investigations, cloning,transgenic, paternity testing and much more. Paternity testing, in general, depends on a kind of DNA called micro-satellites, whose behavior falls within Mendelian genetics: parents pass down their DNA, without fail,to their offspring whereas the offspring inherits its micro-satellite DNA half from each parent.
At the end of last century micro satellite technology was applied in the identification of the lineages of giant pandas. While human DNA testing and giant panda DNA testing are similar in principle, the DNA genetic markers vanes for each species. Thanks to the combined efforts of Chinese and international scientists, various giant panda gene identification kits have been developed. Currently micro satellite approach has proved to be convenient, fast and precise only a small number of individual cells (150 in theory) is required to be reproduced in polymerase chain reaction (PCR), and then there is the result. In the past, blood or body tissue was necessary to conduct the test, but presently that is needed is some shed cells plucked on a cotton ball brushed in the animal’s mouth. For wild animals] the cells on the surface of their scat is all that is needed to test their DNA.
Supported by this technology scientists take some body-issues of the giant panda in question and compare it to tissues from several possible fathers. If the DNA of one of the potentials matches that of a particular panda, then he is identified as the father.Paternity identification has helped to establish the pedigree number, or D, of every giant panda in the world. With these IDs, inbreeding can be avoided, and genetic diversity will be maintained in the world of giant pandas.
This pedigree book aids the concept of optimized mating, which is the scientific process to avoid inbreeding, to become a general practice. In the yearly breeding season, scientists would decide based on the pedigree book as to the best-matched couples. Some of these couples would mate naturally and those that did not, artificial insemination would be conducted.
In the latter case, scientists sometimes rely on frozen semen. Typically natural mating will be followed by artificial insemination, especially the implanting of frozen sperms to guarantee conception.The frozen sperms are collected by researchers in one large amount during the spring in tubes and preserved in liquid nitrogen of minus 196 degrees Celsius. Such low temperatures suspend the metabolism of the sperms, keeping therein a dormant state. Thus one measure of frozen semen can be used more than once.
Ultimate Solution: Reintroduction to the Wild
It has been 50 years since the first cub was delivered in captivity in 1963 and 30 years since impressive breakthrough have been made in the artificial breeding of giant pandas. The estimated 300 giant pandas bore in captivity are more than ambassadors of technological advancement,but are inspirations, that motivate scientists to think farther and more creatively .Presently scientists are hued with a sense of crisis that if giant pandas are bred only to live in Zhu-and-Chen village like conditions at research institutes and zoos,their wild nature and instincts and genetic diversity will be lost. Although it is hard work to create optimal giant panda mating,the focus needs to be on DNA diversity to create a genetically balanced population.
There is no other better way to do this than reintroducing giant pandas into the wild,where their ancestors have lived and prospered for eight million years To achieve this ultimate goal, scientists and conservationists have to work hard and combine concepts.