GeneRegulation160-page7 - Orange patches of fur result when...

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Gene Regulation - 7 Chromosome Inactivation – The Barr Body Females have two X-chromosomes. In most cells, one of them is deactivated (apparently at random) during embryonic development and forms a tightly condensed object that lines the nuclear membrane, called the Barr body. The DNA of the Barr body is not available for use by the cell, a form of gene regulation by chromosome inactivation. The specific alleles for genes carried on the X chromosome that get expressed in any given cell line depends on which X chromosome is not made into a Barr body. The pattern of the calico cat is an example of Barr body expression. Both orange and black pigment alleles are on the X chromosome. The black patches of fur are from cell lines where the orange X chromosome is a Barr body.
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Unformatted text preview: Orange patches of fur result when the black X chromosome becomes the Barr body. The patches of white fur are the expression of a different gene. Eukaryotic Gene Regulation during Transcription Prior to looking a ways in which transcription in eukaryotes can be controlled or regulated, let's look at the eukaryotic gene transcription complex. Eukaryotic Gene Transcription Complex Like the prokaryotic gene, transcription for an eukaryotic gene requires a number of regions, each important to transcription. The components of the eukaryotic transcription complex include: • Control elements • The codable gene including introns and exons • A termination sequence....
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This note was uploaded on 12/29/2011 for the course BIO 151 taught by Professor Edwards during the Spring '10 term at SUNY Stony Brook.

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