Hemochromatosis results in iron overload, which is typically treated by phlebotomy.

Determination of HLA haplotype is based on association of particular haplotype with risk of disease, particularly an auto-immune disease. 

There can be only two alleles representing either the enzyme cutting or not cutting the polymorphic site.

Base excision repair, involved in removal of thymidine dimers, is defective in individuals with xeroderma pigmentosum.

PCR reaction is exponential. After 10 cycles of amplification, one expects approximately 2¹⁰ copies, or around 1000.

A skipped generation for a dominant trait is an example of non-penetrance.

Such a mutation would cause a phenotype in the heterozygous state and therefore would be a dominant trait.

An X-linked trait does not display male to male transmission. Any of the others are possible, including autosomal recessive, if the mother is also heterozygous (pseudo-dominant transmission).

The yeast artificial chromosome can accommodate several hundred thousand base pairs to upwards of a million.

For an inherited trait subject to imprinting, the phenotype will only be expressed when it is inherited from the parent whose copy is expressed in the next generation.

Restriction endonucleases cut double stranded DNA and are made by bacteria, where they cut DNA injected into the cells by bacteriophage.

Urea cycle disorders lead to buildup of ammonia. The mainstay of current treatment is to use substances such as sodium benzoate and sodium phenylacetate to complex with ammonia, forming water soluble compounds that can be excreted in the urine.

A cDNA library is created by using reverse transcriptase to copy mRNA into DNA, which is subsequently cloned. Each cDNA is homologous to a distinct mRNA molecule.

Modification of the protein by addition of mannose-6-phosphate is involved in targeting enzymes to the lysosome.

Gaucher disease is a lysosomal storage disorder that can be treated by enzyme infusion.

A sequence is a set of anomalies that result as a consequence of a single primary malformation.

Haploinsufficiency is believed to explain the developmental anomalies, whereas tumors form as a consequence of homozygous mutation by a tumor suppressor mechanism.

Mullerian-inhibiting substance prevents development of Mullerian ducts into a uterus and fallopian tubes. Absence of the substance would lead to persistence of these structures in a male.

Hox gene products contain a DNA-binding domain and function as transcription factors.

Development of the testes requires the presence and function of SRY.

Cirrhosis in individuals with thalassemia would be the result of chronic iron overload, although chelation therapy can prevent this from occurring.

Carriers for a beta thalassemia mutation are relatively resistant to malaria, which confers a heterozygote advantage in this region of the world.

Carriers for Tay-Sachs disease are most commonly screened by enzyme assay.

The current approach to carrier detection involves testing of a limited panel of mutations, which results in failure to detect some of the rarer CFTR mutations.

A significant proportion of individuals who are homozygous for HFE mutation will not develop signs or symptoms of iron overload. There are only two HFE mutations that account for most affected individuals, and HFE mutation accounts for the majority of cases of hemochromatosis in individuals of northern European descent.