Citation: Lobo, I. & Shaw, K. (2008) Phenotypic range of gene expression: Environmental influence. Obviously, genes are not the only factors that determine phenotype - after all, even identical twins are not exactly alike.
http://www.nature.com/scitable/topicpage/Phenotypic-Range-of-Gene-Expression-Environmental-Influence-581
the mating of two genetically different plants of the same species. Usually, the term is used in reference to the crossing of two pure breeding (homozygous) plants. cystic fibrosis. a genetically inherited disease in children that results in chronic fluid development in the lungs, making breathing difficult.
http://anthro.palomar.edu/mendel/glossary.htm
Citation: Lobo, I. & Shaw, K. (2008) Phenotypic range of gene expression: Environmental influence. Nature Education 1(1):12. Obviously, genes are not the only factors that determine phenotype - after all, even identical twins are not exactly alike.
http://www.nature.com/scitable/topicpage/Phenotypic-Range-of-Gene-Expression-Environmental-Influence-581
The norm of reaction is the theoretical concept that a specific phenotype may have a range of manifestations. In some cases, like human blood type, the range of phenotypes is strictly related to , and the environment has little effect. For other phenotypes, like height in humans, the norms of reaction are much wider.
http://www.nature.com/scitable/topicpage/Phenotypic-Range-of-Gene-Expression-Environmental-Influence-581
Individuals who have two copies of the same allele are said to be homozygous at that locus. Individuals who receive different alleles from each parent are said to be heterozygous at that locus. The alleles an individual has at a locus is called a genotype. The genotype of an organism is often expressed using letters. The visible expression of the genotype is called an organism’s phenotype.
http://scienceprimer.com/Alleles-genotype-phenotype
Making the world better, one answer at a time. Pleiotropy. Pleiotropy occurs when one gene influences multiple, seemingly unrelated phenotypic traits, an example being phenylketonuria, which is a human disease that affects multiple systems but is caused by one gene defect.
http://www.answers.com/Q/When_a_gene_has_the_ability_to_influence_several_different_aspects_of_the_phenotype_of_an_organism_this_is_referred_to_as
Thus, mutations in any one of the genes that affect tyrosine synthesis or may affect multiple body systems. These and other instances in which a single gene affects multiple systems and therefore has widespread phenotypic effects are referred to as indirect or secondary pleiotropy (Grüneberg, 1938; Hodgkin, 1998). Other examples of both direct and indirect pleiotropy are described in the sections that follow.
http://www.nature.com/scitable/topicpage/Pleiotropy-One-Gene-Can-Affect-Multiple-Traits-569
alternate forms or varieties of a gene. The alleles for a trait occupy the same locus or position on homologous chromosomes and thus govern the same trait. However, because they are different, their action may result in different expressions of that trait.
http://anthro.palomar.edu/mendel/glossary.htm
Making the world better, one answer at a time. Pleiotropy occurs when one gene influences multiple, seemingly unrelated phenotypic traits, an example being phenylketonuria, which is a human disease that affects multiple systems but is caused by one gene defect.
http://www.answers.com/Q/When_a_gene_has_the_ability_to_influence_several_different_aspects_of_the_phenotype_of_an_organism_this_is_referred_to_as
Citation: Lobo, I. (2008) Pleiotropy: One Gene Can Affect Multiple Traits. Nature Education 1(1):10. How can a mutation in one single gene cause a disease with a wide range of symptoms? This situation is referred to as pleiotropy, and it has been identified in a wide range of species, even humans.
http://www.nature.com/scitable/topicpage/Pleiotropy-One-Gene-Can-Affect-Multiple-Traits-569
when a gene has the ability to influence several different aspects of the phenotype of an organism, this is referred to as
The ability to influence several different aspects of the phenotype of an Organismn has Pleiotropy. When a gene has the ability to influence several different aspects of the phenotype of an organism, this is referred to as pleiotropy.  