Difference Between Monosomy and Trisomy

关键差异 - 单穿体与三体性

Chromosomal nondisjunction causes abnormal chromosome numbers in daughter cells. It can occur duringcell divisioninmitosis and meiosis.As a result of nondisjunction in meiosis,aneuploidindividuals are developed after the fertilization. Aneuploidy is amutationin which chromosomal number is abnormal. A normal diploid cell (2n) contains a total of 46 chromosomes arranged in 23 pairs. A normal单倍体细胞（n），这是gamete, contains 23 chromosomes. Aneuploids can have more or fewer chromosomes than the normal number. Trisomy and monosomy are two such numerical chromosome abnormalities which cause birth defects.The term monosomy is used to describe the chromosomal abnormality in which one chromosome is absent from a pair ofhomologous chromosomes。三体术语用于描述异常的染色体数，其中三种染色体（通常对 +额外的染色体）存在于一种同源染色体中。这是单色和三体性之间的关键区别。因此，单穿体的非整倍体条件为2N-1，而三体性为2n+1。

内容
1.Overview and Key Difference
2.What is Monosomy
3.What is Trisomy
4.Side by Side Comparison – Monosomy vs Trisomy
5.概括

What is Monosomy?

The word monosomic refers ‘one chromosome’. The term monosomy is used to explain the aneuploid condition which lacks one member of a homologous chromosome pair. Due to this condition, resulting cells will contain only 45 chromosomes instead of the usual 46 chromosomes. Cells show 2n-1 chromosomes in each cell of the body. For example, monosomy ofsex chromosomeleads to Turner’s syndrome in which individuals bear only one X sex chromosome. Another example of monosomy is Cri du chat syndrome which is caused by partial monosomy of chromosome 5. 1p36 deletion syndrome is another syndrome which is caused due to partial monosomy of chromosome 1.

Monosomy results in deleterious effects in individuals. Missing chromosome causes changes in the overall gene balance of chromosome set. It also allows any harmful recessive allele on the single chromosome to be hemizygous and to be expressed phenotypically.

What is Trisomy?

三体术语描述了通常的同源染色体中存在额外的染色体的状况。一对同源染色体对中有三个副本。人体的每个细胞总共包含47个染色体，而不是通常的46个染色体。例如，三体第21或Down syndrome发生的原因是存在三个染色体21的副本。三体第18章是另一个例子，其中三个染色体第18拷贝比通常的一对，导致综合征称为爱德华兹综合征。PATAU综合征是由于染色体数字13中存在三个染色体而引起的。还可以看到性染色体对三体。如果发生这种情况，可能会发生几种异常性染色体条件，例如XXX（三重X综合征），XYY和XXY（KlineFelter综合征）。

What is the difference between Monosomy and Trisomy?

单肌与三体
Monosomy is a type of aneuploidy in which only one copy is present instead of two	Trisomy is a type of aneuploidy in which three copies of a particular chromosome is present instead of two.
Chromosome Number
Cells contain a 2n-1 number of chromosomes (total of 45).	Cells bear a 2n+1 number of chromosomes (total of 47).
Syndrome
Turner’s syndrome, Cri du chat syndrome, and 1p36 deletion syndrome are caused by this.	Down syndrome, Edwards syndrome, Patau syndrome, Klinefelter syndrome, Warkany syndrome 2, and triple X are caused by this.

概括-单肌与三体

细胞分裂是一种细胞过程，可为各种目的创建新细胞。在某些情况下，细胞分裂显示染色体析识上的错误。它被称为染色体非结合，在有丝分裂和减数分裂过程中发生，导致二倍体和单倍体细胞具有异常的染色体数。单肌和三体性是两种数字染色体异常。单肌是一种描述正常染色体中没有一个副本的疾病。三体是一种描述特定染色体的三个副本而不是两个副本的疾病。两种情况都通过在整体遗传组成中失衡而在个体中产生有害影响。

Image Courtesy:
1.没有提供机器可读作者的“ 45，x”。CAT〜Commonswiki假设（基于版权主张）。-(CC BY-SA 3.0)viaCommons Wikimedia
2.“21 trisomy – Down syndrome”By U.S. Department of Energy Human Genome Program. – (Public Domain) viaCommons Wikimedia