文档介绍：the Basis of ics
Medical ics
Cellular Basis of ics
Structure of Eukaryote
1. Strongly condensed
Euchromatin & heterochromatin
Euchromatin
Heterochromatin
Chromotin & Chromosome
2. ic inertia
3. Be late to replicate
a. Constitutive heterochromatin
b. Facultative heterochromatin
Sex chromotin
X chromatin
X body
Barr body
Chromotin & Chromosome
Sex chromotin
Lyon hypothesis (1961)
1. Inactivation of all but one X chromosome
2. Happened at an early stage of embryogenesis
3. Happened on a random basis and maintained in all descendant cells
pensation
Chromotin & Chromosome
Sex chromotin
Y-chromatin
Chromotin & Chromosome
Sex Determining Mechanism
Chromosomal mechanisms (XY)
Y chromosome
Two sex chromosomes of different sizes, X is larger
TDF:testis-determining factor
SRY:sex-determining region of Y chromosome
Females are XX, males are XY
Males determine the sex of the offspring
Molecular Basis of ics
bp
P
A
T
G
C
Structure of DNA
Deoxyribose