What is a variation of a gene expression called?
An allele is a variant form of a gene. Some genes have a variety of different forms, which are located at the same position, or genetic locus, on a chromosome. Humans are called diploid organisms because they have two alleles at each genetic locus, with one allele inherited from each parent.
What is the difference between variable expressivity and reduced penetrance?
Variable expressivity refers to the range of signs and symptoms that can occur in different people with the same genetic condition. As with reduced penetrance, variable expressivity is probably caused by a combination of genetic, environmental, and lifestyle factors, most of which have not been identified.
What is the difference between pleiotropy and variable expressivity?
Pleiotropy is the condition whereby a single gene mutation has multiple consequences in numerous tissues. Even in the same family, two individuals carrying the same mutant genes may have different disease manifestations. Expressivity is defined as the severity of the phenotype.
Is Cystic Fibrosis variable expressivity?
Finally, although lung disease is almost fully pen- etrant late in advanced stages of the disease, its expressivity is the most variable of all clinical manifestations in CF due to more complex gene-environment interactions involving both primary and secondary genetic factors as well as the environ- ment.
What is meant by variable expressivity?
Variable expressivity refers to the range of signs and symptoms that can occur in different people with the same genetic condition.
What is continuous variation?
Continuous variation is where the different types of variations are distributed on a continuum. On the other hand, discontinuous variation is where the different types of variations are placed into discrete categories.
What is an example of variable expressivity?
Variable expressivity refers to the degree in which a genotype is phenotypically expressed. For example, multiple people with the same disease can have the same genotype but one may express more severe symptoms, while another carrier may appear normal.
How big is the CFTR gene?
The CFTR gene itself spans only 189.36 kb; however, the immediate promoter can be extended as far as 20.9 kb upstream, where the CTCF-dependent insulator element is located—the expanded promoter region includes the regulatory binding element required for proper gene expression (Blackledge et al. 2007).
What is CFTR 5T?
Cystic fibrosis is caused by mutations in the cystic fibrosis transmembrane regulator (CFTR) gene. The 5T allele in intron 8 (IVS8) causes abnormal splicing in the CFTR gene, and is associated with lung disease when it occurs in cis with a missense mutation in the CFTR gene, R117H.
What is an example of expressivity?
Another example of expressivity at work is the occurrence of extra toes, or polydactyly, in cats. The presence of extra toes on a cat’s paw is a phenotype that emerges in groups of cats who have interbred for generations.
What is continuous variation in genes?
Continuous variation of a character shows an unbroken range of phenotypes in the population. Metric characters such as height, weight, and color intensity provide good examples of continuous variation.
What is an example of continuous variation?
Human height is an example of continuous variation. It ranges from that of the shortest person in the world to that of the tallest person. Any height is possible between these values. So it is continuous variation.