Changes

[[Mutation]]s are simply variations in DNA sequence between individuals. The vast majority of spontaneous mutations in DNA are called "neutral" because they do not affect the [[phenotype|observable traits]] of the individual organism. Others can have beneficial effects and some can disrupt important functions  Differential distribution of various types of neutral mutations within the population is the basis for modern [[DNA fingerprinting]].  It is mutations in DNA, giving rise to novel alleles ("versions" of a gene), which cause phenotypic variations between individuals of a particular species.  For instance, in humans, single-gene mutations are responsible for differences in [[ABO blood type]], eye color, hair color, and even the ability to taste certain molecules.  Sadly, there are also thousands of mutations known to cause human disease; notably sickle-cell anemia, a few rare forms of autism, and (when the mutations spontaneously occur in a somatic cell) various types of cancer.  That said, it is important to note that most phenotypic traits (e.g. height) and hereditary diseases arise as the net effect of several different genetic variations.

[[Mutation]]s are simply variations in DNA sequence between individuals. The vast majority of spontaneous mutations in DNA are called "neutral" because they do not affect the [[phenotype|observable traits]] of the individual organism. Others can have beneficial effects and some can disrupt important functions  Differential distribution of various types of neutral mutations within the population is the basis for modern [[DNA fingerprinting]].  It is mutations in DNA, giving rise to novel alleles ("versions" of a gene), which cause phenotypic variations between individuals of a particular species.  For instance, in humans, single-gene mutations are responsible for differences in [[ABO blood type]], eye color, hair color, and even the ability to taste certain molecules.  Sadly, there are also thousands of mutations known to cause human disease; notably sickle-cell anemia, a few rare forms of autism, and (when the mutations spontaneously occur in a somatic cell) various types of cancer.  That said, it is important to note that most phenotypic traits (e.g. height) and hereditary diseases arise as the net effect of several different genetic variations.

Usually a mutation is harmless if present in only one of the two or more genomes in same cell (it is said most of mutations are recessive), or even may be beneficial. Offspring of the parents who are already genetically related often inherits the same mutation in both genomes, so diseases are more frequent. If the mutation is diagnosed early in the life, diet and other similar measures may be applied, resulting a normal life later.<ref name=Al2015>{{cite journal|last1=Al Hafid|first1=N|last2=Christodoulou|first2=J|title=Phenylketonuria: a review of current and future treatments.|journal=Translational pediatrics|date=October 2015|volume=4|issue=4|pages=304–17|pmid=26835392}}</ref>

Usually a mutation is harmless if present in only one of the two or more genomes in same cell (it is said most of mutations are recessive), or even may be beneficial. Offspring of the parents who are already genetically related often inherits the same mutation in both genomes, so diseases are more frequent. If the mutation is diagnosed early in the life, sometimes diet and other similar measures may be applied, resulting a normal life later.<ref name=Al2015>{{cite journal|last1=Al Hafid|first1=N|last2=Christodoulou|first2=J|title=Phenylketonuria: a review of current and future treatments.|journal=Translational pediatrics|date=October 2015|volume=4|issue=4|pages=304–17|pmid=26835392}}</ref>

[http://www.ncbi.nlm.nih.gov/omim OMIM] (Online Mendelian Inheritance in Man), is an online database of genes known to be mutated in disease states.  [[Mendelian inheritance]] refers to the inheritance pattern observed in traits that are determined by a single gene.  This pattern was first discovered by [[Gregor Mendel]], an Austrian monk, during his work with pea plants from 1856-1863.  Although Mendel published his work in 1866, it's significance was largely ignored until it was rediscovered in the early 20th century; more than two decades after his death.

[http://www.ncbi.nlm.nih.gov/omim OMIM] (Online Mendelian Inheritance in Man), is an online database of genes known to be mutated in disease states.  [[Mendelian inheritance]] refers to the inheritance pattern observed in traits that are determined by a single gene.  This pattern was first discovered by [[Gregor Mendel]], an Austrian monk, during his work with pea plants from 1856-1863.  Although Mendel published his work in 1866, it's significance was largely ignored until it was rediscovered in the early 20th century; more than two decades after his death.