Search results
Results from the WOW.Com Content Network
Inbreeding coefficients of various populations in Europe and Asia. Offspring of biologically related persons are subject to the possible effects of inbreeding, such as congenital birth defects. The chances of such disorders are increased when the biological parents are more closely related.
Darwin's wife, Emma, was his first cousin, and he was concerned about the impact of inbreeding on his ten children, three of whom died at age ten or younger; three others had childless long-term marriages. [16] [17] [18] Humans do not seek to completely minimize inbreeding, but rather to maintain an optimal amount of inbreeding vs. outbreeding.
Multiple studies have established consanguinity as a high cause for birth defects and abnormalities. A risk of autosomal recessive disorders increases in offspring coming from consanguineous marriages due to the increased likelihood of receiving recessive genes from cognate parents. [ 2 ]
Genetic causes of birth defects include inheritance of abnormal genes from the mother or the father, as well as new mutations in one of the germ cells that gave rise to the fetus. Male germ cells mutate at a much faster rate than female germ cells, and as the father ages, the DNA of the germ cells mutates quickly.
Risk factors for mental illness include psychological trauma, adverse childhood experiences, genetic predisposition, and personality traits. [7] [8] Correlations between mental disorders and substance use are also found to have a two way relationship, in that substance use can lead to the development of mental disorders and having mental disorders can lead to substance use/abuse.
Genetic purging is the increased pressure of natural selection against deleterious alleles prompted by inbreeding. [1]Purging occurs because deleterious alleles tend to be recessive, which means that they only express all their harmful effects when they are present in the two copies of the individual (i.e., in homozygosis).
A review of the genetics of inbreeding depression in wild animal and plant populations, as well as in humans, led to the conclusion that inbreeding depression and its opposite, heterosis (hybrid vigor), are predominantly caused by the presence of recessive deleterious alleles in populations. [7]
Since the advent of forms of prenatal diagnosis, such as amniocentesis and ultrasound, it has become possible to detect the presence of congenital disorders in the fetus before birth. Specifically, disability-selective abortion is the abortion of fetuses that are found to have non-fatal mental or physical defects detected through prenatal ...