BIOLOGY 2C03 Chapter Notes - Chapter 3: Barr Body, Rna Interference, Histone Methyltransferase
26 Jan 2017
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3. 6 dosage compensation equalizes the expression of sex- Dosage compensation: any mechanism that compensates for differences in the number of copies of genes due to the different chromosome constitutions of males & females. Note: each individual cell expresses allelic information of one of those chromosomes, with all descendant cells maintaining same inactivation pattern as to original ancestral cell. Female carriers of x-linked recessive traits display phenotypic manifestation of recessive allele. Calico & tortoiseshell coat-color patterning in female cats. Females with allele for black coat color on one x chromosome & yellow coat color on homologous x chromosome have patches of fur corresponding to portions of skin where each x chromosome is active. Specific pattern of x inactivation is unique to each female cat embryo & patterns of cellular migration are variable. Note: not all genes on inactivated x chromosome are transcriptionally silent, but transcription of x-linked genes that remain active is reduced by ~
