PCB 4594 Lecture Notes - Lecture 6: Barr Body, X-Inactivation, Aromatase
Aromatase
Enzyme that converts testosterone into estradiol
Chromosomal Aneuploidy
Loss of one or more entire chromosome, generally lethal
Dosage Compensation in humans
X inactivation in females
Dosage Compensation in Drosophila
X hypertranscription in males
Can females be mosaic? How?
Due to random x chromosome inactivation
ex. tortoiseshell cat
N-1 rule
X chromosome -1
-You have to have one chromosome left
So if there are
XX, 0 barr body
XXX, 2 barr bodies
XXXX, 3 barr bodies
Would Barr bodies exhibit more methylation or more acetylation?
Methylation
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Document Summary
Loss of one or more entire chromosome, generally lethal. Due to random x chromosome inactivation ex. tortoiseshell cat. Encodes a large untranslated rna that is localized to the nucleus. Synthesis of theory of natural selection, mendel"s genetics, and mathematical theory of genetics. Accumulation of mutations that have no selective consequence. Accounts for a significant amount of change in primary sequence of dna. Mutations are not selected for but spread through a population. Change with effect that does not affect fitness. Features that not only look similar between 2 species but also descend from a common ancestor which had an earlier version of the feature. Features that look similar but arose separately due to selective pressure. Estimate of average changes in dna sequences for a given period of time. -> do not specify the same things in different organisms. Segment that it"s usually found in, causes segment to take on characteristics of anterior segment.
