Duchenne Muscular Dystrophy (DMD)is Normally an X-Linked Recessive Human Disease

question 47

Essay

Duchenne muscular dystrophy (DMD)is normally an X-linked recessive human disease affecting boys.Girls afflicted with DMD are rare.Cytogenetic studies of several girls with DMD have in each case revealed that these individuals carry X-autosome translocations.The autosomes vary, but the breakpoint on the X in every case is in band p21, which is the location of the DMD gene.Cytogenetic studies further revealed that in all cells studied in such DMD girls the normal X chromosome exists as a Barr body.How might these observations account for the existence of DMD-affected girls? Why is only the normal X seen as a Barr body?

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Definitions:

Rehearsal

A cognitive process in which information is repeated over and over as a possible way of learning and remembering it.

Chunking

A memory technique that involves breaking down information into smaller, manageable groups or chunks to facilitate easier recall.

Implicit Memory

Refers to memories that are recalled without conscious effort, such as procedural memories for tasks.

Ku Klux Klan

A white supremacist hate group in the United States, known for racist terrorism, including lynching and intimidation against African Americans and other minority groups.