MindMap Gallery Biology - Human chromosomes and chromosomal aberrations
Human chromosomes and chromosomal aberrations include the basic characteristics of human chromosomes, the structure of chromosomes, and the observation methods of human chromosomes.
Edited at 2023-12-13 23:03:55One Hundred Years of Solitude is the masterpiece of Gabriel Garcia Marquez. Reading this book begins with making sense of the characters' relationships, which are centered on the Buendía family and tells the story of the family's prosperity and decline, internal relationships and political struggles, self-mixing and rebirth over the course of a hundred years.
One Hundred Years of Solitude is the masterpiece of Gabriel Garcia Marquez. Reading this book begins with making sense of the characters' relationships, which are centered on the Buendía family and tells the story of the family's prosperity and decline, internal relationships and political struggles, self-mixing and rebirth over the course of a hundred years.
Project management is the process of applying specialized knowledge, skills, tools, and methods to project activities so that the project can achieve or exceed the set needs and expectations within the constraints of limited resources. This diagram provides a comprehensive overview of the 8 components of the project management process and can be used as a generic template for direct application.
One Hundred Years of Solitude is the masterpiece of Gabriel Garcia Marquez. Reading this book begins with making sense of the characters' relationships, which are centered on the Buendía family and tells the story of the family's prosperity and decline, internal relationships and political struggles, self-mixing and rebirth over the course of a hundred years.
One Hundred Years of Solitude is the masterpiece of Gabriel Garcia Marquez. Reading this book begins with making sense of the characters' relationships, which are centered on the Buendía family and tells the story of the family's prosperity and decline, internal relationships and political struggles, self-mixing and rebirth over the course of a hundred years.
Project management is the process of applying specialized knowledge, skills, tools, and methods to project activities so that the project can achieve or exceed the set needs and expectations within the constraints of limited resources. This diagram provides a comprehensive overview of the 8 components of the project management process and can be used as a generic template for direct application.
Chromosome structure and chromosomal aberrations
Basic characteristics of human chromosomes
Chromosomes are the carriers of DNA
Classification
euchromatin
Low degree of coiling and coiling, light staining, and transcriptionally active
heterochromatin heterochromatin
High degree of coiling and coiling, dark staining, little or no transcriptional activity
Structural heterochromatin
Highly repetitive DNA sequences with no transcriptional activity are generally distributed at centromeres, telomeres, subconstrictions, and the distal end of the long arm of the Y chromosome.
functional heterochromatin
Facultative heterochromatin, present in specific cells or specific developmental stages, is formed by condensation and transformation of euchromatin
X body, Bartholin body
Leon hypothesis lyon
early embryonic stage
random
permanently and clonally reproduced
completely
Follow N-1
tortoiseshell cat
mechanism
The transcription product of Xist is a long non-coding RNA, which prefers to bind to the chromosome where it is transcribed, and gradually wraps up the entire chromosome.
type
centromere
1/2-5/8
matacentric
submetacentromere
5/8-5/8
submetacentic
acrocentromere
7/8-end
arocentric
Telocentre
telocentric
structure of chromosomes
telomeres
end of chromosome arm
primary constriction
Narrowing of the junction between chromosome arms and centromeres
secondary constriction
a constriction in a chromosome arm
Follow the body
acrocentric globular structure at the end of a chromosome
How to observe human chromosomes
Karyotyping
Karyotype
karyotype: Based on the relative size of chromosomes, centromere position, arm length, presence or absence of satellites and other characteristics, the image formed by grouping and arranging all the chromosomes in a somatic cell in a certain order is called a karyotype.
The karyotype of the cells to be tested is analyzed for chromosome number and morphological characteristics to determine whether it is consistent with the normal karyotype, which is called karyotype analysis.
Human chromosome non-banding karyotype
The entire chromosome is uniformly colored except for centromeres and secondary constrictions.
Description: Total number of chromosomes, sex chromosome composition
Normal female: 46,XX
Can only roughly reflect the chromosome structure
Human chromosome banding karyotyping
Specific staining of metaphase chromosomes to display inherent banding patterns to increase the ability to resolve the fine structures of chromosomes
Giemsa staining, which can obtain approximately 320 bands, is the most commonly used banding method.
Banding technology for the entire chromosome: G-banding, Q-banding, R-banding, etc.
Chromosome local banding technology: C-banding (centromere), T-banding (telomere), N-banding (nucleolar tissue area), etc.
Recording rules for banding karyotypes (ISCN)
Chromosome serial number, arm symbol, region symbol, band serial number
High resolution: sub-zone, sub-sub-zone
chromosomal aberrations
Number distortion
euploidy change
The number change is an integer multiple of the haploid
triploidy
Double female fertilization
The sperm combines with an abnormal egg cell that contains two sets of chromosomes to form a triploid zygote.
fertilization of two males
Two sperm enter the same egg cell to form a triploid zygote
tetraploid
endoreplication, endomitosis
DNA replicates twice, but cells divide only once
Aneuploidy changes
The number of chromosomes in somatic cells increases or decreases by one or several chromosomes based on 2n
hyperdiploidy
2nx
hypodiploidy
2n-x
Chromosome deletion or nondisjunction
缺失
未与纺锤丝连接
移动过慢
不分离
减一
减二
有丝
卵裂
Structural distortion
(1)Missing
Refers to the loss of a certain segment of a chromosome and the genes it carries.
(2) Repeat
Refers to the phenomenon of mutation caused by the addition of the same segment on a chromosome
(3)Inversion
After two breaks occur on a chromosome, a certain segment and the gene sequence it carries are reversed 180°, rejoined and cause mutation.
(4) Translocation
Refers to an aberration in which a certain segment is transferred between two pairs of non-homologous chromosomes. Usually the two parties exchange certain sections, which is called mutual castling.
Human chromosomal polymorphisms
Chromosomal polymorphism: Small, constant but non-pathological differences in chromosome structure and intensity of chromosome coloring between individuals.
DNA polymorphism
VNTR
Number of repeats of tandem repeats
variable number of tandem repeats
individual identification
STR
short tandem repeats
functions of human chromosomes
Ensure equal separation during cell division
Maintain genome stability
Participate in gene expression regulation
sex determination
Sex chromosomes determine gender
Gender determined at fertilization
Y means male
Mutations or translocations can cause hermaphroditism
SRY sex-determining gene
Involved in genome variation
sister chromatid exchange (SCE)
The two sister chromatids of a chromosome are broken at the same position at the same time and then rejoin after exchanging the broken fragments. This is called sister chromosome crossing. Related to DNA damage repair Asymmetric exchange can generate new alleles
The fundamental mechanism of genetic diversity: homologous recombination of homologous chromosomes
Xp22.31 x chromosome short arm region 2 zone 2 subband 3rd subband first subband