Aneuploidy can arise in several ways

Chromosome may be lost during mitosis or meiosis.

The small chromosome generated by a Robertsonian translocation may be lost in mitosis or meiosis.

Aneuploidy may arise through nondisjunction.

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#Id: 9183

#Unit 11. Evolution and Behavior

The selection gradient measures the strength of directional selection acting on a quantitative trait.

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#Id: 7027

#Unit 11. Evolution and Behavior

Proximate causes - The subject of cell biology, neurobiology, and many other biological disciplines

Ultimate causes - Their historical causes, especially the action of natural selection

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#Id: 8583

#Unit 2. Cellular Organization

Lamins 

contribute to genome organization as well as to the rigidity of the nucleus through linkages to the

cytoskeleton involving proteins with SUN and KASH domains

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#Id: 3998

#Unit 2. Cellular Organization

One approach is to measure the effect of nicking the DNA. Unconstrained supercoils are released by nicking, whereas constrained supercoils are unaffected. Nicking releases -50% of the overall supercoiling.

Another approach uses the crosslinking reagent psoralen, which binds more readily to DNA when it is under torsional tension. The reaction of psoralen with E. coli DNA in vivo corresponds to an average density of 1 negative super helical turn/200 bp (sigma = -0.05).

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#Id: 9629

#Unit 4. Cell Communication and Cell Signaling

c-Cbl contains: 

a domain that binds directly to phosphorylated EGF receptors

a RING finger domain, which recruits ubiquitin-conjugating enzymes and mediates transfer of ubiquitin to the receptor