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Teratogens are substances that may cause non-heritable birth defects via a toxic effect on an embryo or fetus. [1] Defects include malformations, disruptions, deformations, and dysplasia that may cause stunted growth, delayed mental development, or other congenital disorders that lack structural malformations. [2]
Such disorders include cystic fibrosis, [27] sickle cell disease, [28] phenylketonuria [29] and thalassaemia. [ 30 ] Hereditary defects in enzymes are generally inherited in an autosomal fashion because there are more non-X chromosomes than X-chromosomes, and a recessive fashion because the enzymes from the unaffected genes are generally ...
An acquired characteristic is a non-heritable change in a function or structure of a living organism caused after birth by disease, injury, accident, deliberate modification, variation, repeated use, disuse, misuse, or other environmental influence. Acquired traits are synonymous with acquired characteristics.
The following is a list of genetic disorders and if known, type of mutation and for the chromosome involved. Although the parlance "disease-causing gene" is common, it is the occurrence of an abnormality in the parents that causes the impairment to develop within the child. There are over 6,000 known genetic disorders in humans.
Trinucleotide repeat disorders also follow a non-Mendelian pattern of inheritance. These diseases are all caused by the expansion of microsatellite tandem repeats consisting of a stretch of three nucleotides. [23] Typically in individuals, the number of repeated units is relatively low.
De novo mutations, by definition, are present in the affected individual but absent from both biological parents' genomes. These mutations can occur in any cell of the offspring, but those in the germ line (eggs or sperm) can be passed on to the next generation.
Modifying a person's non-heritable DNA with the goal of improving one's medical condition is generally accepted and has a plethora of ethical protocols monitoring such procedures. [19] This includes modifications like organ donation, bone marrow transplants, and types of gene therapies, all of which consider cultural and religious values. [19]
Human genetics is the study of inheritance as it occurs in human beings.Human genetics encompasses a variety of overlapping fields including: classical genetics, cytogenetics, molecular genetics, biochemical genetics, genomics, population genetics, developmental genetics, clinical genetics, and genetic counseling.