A sharing by Ling Sing Lin
Egyptian Inbreeding
Pharaohs of ancient Egypt were considered sons of God and not expected to marry ordinary people. Hence intermarriages between brother and sister were common. The short stature of mummified pharaohs support this belief of inbreeding.
The Hapsburg Jaw
Generations of inbreeding among close relatives in the Spanish Hapsburg family resulted in the “Hapsburg jaw”, with Charles Ii being a good example. He was infertile, had a tongue so large he could barely speak, and had an offset jaw such that his top and bottom teeth couldn’t meet. He also had trouble walking.
Henri-Toulouse Lautrec
This French artist was born to aristocratic lineage. However, his grandmothers were sisters and his parents were first cousins. He fractured both legs as a teenager and the fracture never healed, probably due to a congenital bone disease. Although his torso was adult sized, his legs never grew. He had a short stature of 4 feet 8 inches. He spent much of his life recuperating from ailments. Because he couldn’t take part in sports, he spent his time painting.
Genetic Diseases
Not all genetic diseases result from consanguineous marriages, ie marrying someone closely related. Most people avoid marrying close relatives because they fear having abnormal children. Many people in fact carry defective genes which are not manifested, as these defective genes are in the recessive mode. Only when they marry another person with the same defective recessive gene, an off spring who inherits both the defective recessive genes, will manifest the disease, eg albinism. Both parents appear normal, yet they have an abnormal child..
Sperm Donation
The maximum number of times a donor’s sperm can be used in UK is 10 times, in US it is 25 times, and Singapore has restricted it to 3 times. This is to reduce the chance of half siblings marrying unintentionally. I recall reading about a Dutch sperm donor who may have fathered 550 children, by donating to multiple fertility clinics which do not share data.
Genetic Advantage of Multiracial Offspring
Because of a more diverse gene pool, such a child is less likely to receive two recessive genes of the same defect. In fact, such offspring are likely to be more attractive, fertile, intelligent and athletic.
Pet Inbreeding
Pet inbreeding is deliberately and routinely practiced as part of pedigree dog breeding to get a particular look. However, this practice results in an increased incidence of inherited diseases and serious health problems. The lifespan of inbred pets is generally shorter than that of mongrels.
Moral of the Story
Most people are aware of the dangers of consanguineous marriages and do avoid marrying close relatives. But I am not so sure they are aware that their purebred dog may be inbred with the attendant problems of serious ill health, high vet bills and shorter lifespans. Mixed breed dogs are a better option.
lingsinglin
Dr Ling Sing Lin is a medical doctor by training. She worked in MOH HQ for many years, in policy making and administrative positions, until her retirement.
