Exam 9: Extranuclear Inheritance

Approximately one in5000 humans either have a mitochondrial DNA disorder or are at risk for developing such a disorder. What future approach involving nuclear transplantation might be available to treat mtDNA-based human disorders?

List three criteria indicating that a human disorder may be attributable to genetically altered mitochondria.

Molecular/structural orientations (gradients) in an egg are thought to play a significant role in development. What is the origin of such gradients? What evidence indicates that the maternal genotype is involved in providing such gradients?

Poky strains in yeast result from suppressive mutations in chloroplast DNA.

How are reciprocal crosses used to identify cases of extrachromosomal inheritance? What criteria would one use to state that a particular mode of inheritance is extrachromosomal?

The inheritance of the petite phenotype in yeast is complicated by an interaction of mitochondrial and nuclear genes. What are these complications? Which three categories of petites are commonly described?

It is safe to say that a maternal effect is caused by the genotype, not the phenotype, of the parent producing the egg.

What is the name of a form of extrachromosomal inheritance that is due to transmission of symbiotic or parasitic microorganisms?

To which of the following does the term heteroplasmy refer?

Inheritance of the green and white patches phenotype in Mirabilis jalapa (four o'clocks) is an example of maternal influence.

Maternal-effect patterns result when nuclear gene products controlled by the maternal genotype condition the egg and influence early development. Give two examples of maternal effects.

List two classes of extrachromosomal inheritance and give an example of each.

Kearns-Sayre syndrome (KSS) results in progressive loss of vision and hearing, as well as heart defects. What is the genetic basis for this disease?

In what way do mitochondrial mutations influence phenotype?

Direction of shell coiling in Lymnaea peregra is strongly and most directly influenced by_______.

Which of the following organelles are involved in the general category of organelle heredity?

How do mitochondria and chloroplasts determine phenotypes? Which characteristics of mitochondria and chloroplasts allow such phenotypes to be inherited? Provide specific examples to illustrate your response.