Changes

===Recessive/Dominant===

===Recessive/Dominant===

The more common, and less scientifically-meaningful, is the [[recessive]]/[[dominant]] relationship. A recessive allele must be homozygous in order for the [[phenotype]] to be observed, whereas the phenotype caused by a dominant allele may mask recessive alleles.

The more common, and less scientifically meaningful, is the [[recessive]]/[[dominant]] relationship. A recessive allele must be homozygous in order for the [[phenotype]] to be observed, whereas the phenotype caused by a dominant allele may mask recessive alleles.

More complex interactions may occur, such as co-dominance, when two dominant alleles may both manifest a phenotype. The weakness with this classification system is that an allele’s behavior depends on which other alleles are present, and so an allele may be recessive in some cases, and dominant (or co-dominant) in another.

More complex interactions may occur, such as co-dominance, when two dominant alleles may both manifest a phenotype. The weakness with this classification system is that an allele's behavior depends on which other alleles are present, and so an allele may be recessive in some cases, and dominant (or co-dominant) in another.

====Example====

====Example====

====Neomorph====

====Neomorph====

A neomorphic allele has a novel or new function. These are often caused by the fusion of two existing genes, creating a hybrid protein product, or the fusion of one gene’s control or regulatory features with the protein encoding region of another gene, causing a gene to be expressed in a new pattern in an organism

A neomorphic allele has a novel or new function. These are often caused by the fusion of two existing genes, creating a hybrid protein product, or the fusion of one gene's control or regulatory features with the protein encoding region of another gene, causing a gene to be expressed in a new pattern in an organism

====Antimorph====

====Antimorph====

An antimorphic allele inhibits or interferes with the function of another allele, causing a reduction in gene function of a normal allele.

An antimorphic allele inhibits or interferes with the function of another allele, causing a reduction in gene function of a normal allele.

This is the scientifically preferred nomenclature, since an allele’s morphy is dependent upon its relationship to a normal, or “wild-type,” allele.  In general, amorphic and hypomorphic alleles are classified as “loss-of-function,” and often coincide with “recessive” alleles; hypermorphic, neomorphic, and antimorphic alleles generally are referred to as “gain-of-function,” and often coincide with dominant alleles.

This is the scientifically preferred nomenclature, since an allele's morphy is dependent upon its relationship to a normal, or “wild-type,” allele.  In general, amorphic and hypomorphic alleles are classified as “loss-of-function,” and often coincide with “recessive” alleles; hypermorphic, neomorphic, and antimorphic alleles generally are referred to as “gain-of-function,” and often coincide with dominant alleles.

[[Category:Genetics]]

[[Category:Genetics]]