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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.
Inbreeding can lead to inbreeding depression within the population, and this can cause fewer offspring, more birth defects, more individuals prone to disease, decreased survival and reproduction (fitness), and decreased genetic diversity within the population.
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).
Population bottleneck followed by recovery or extinction. A population bottleneck or genetic bottleneck is a sharp reduction in the size of a population due to environmental events such as famines, earthquakes, floods, fires, disease, and droughts; or human activities such as genocide, speciocide, widespread violence or intentional culling.
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.
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] According to population based case-control studies, a ...
Inbreeding avoidance, or the inbreeding avoidance hypothesis, is a concept in evolutionary biology that refers to the prevention of the deleterious effects of inbreeding. Animals only rarely exhibit inbreeding avoidance. [ 1 ]
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 ...