Thekey differencebetween Barr body and polar body is thatBarr body is the inactiveX染色体in asomatic cell雌性,而极性身体是三个单倍体之一gametesthat do not become an egg at the end ofoogenesis.
Barr体和极性体是女性中发现的两个不同的结构。Barr体是一种不活跃的染色体,而极性体是卵子发生过程中形成的小单倍体细胞。因此,巴尔体是染色体,而极体是单倍体细胞。两者都是女性独有的。然而,在体细胞中发现了bar骨体,而在有性繁殖过程中发现了极性体。
内容
1.Overview and Key Difference
2.巴氏小体是什么
3.What is Polar Body
4.巴尔身体和极性身体之间的相似之处
5.Side by Side Comparison – Barr Body vs Polar Body in Tabular Form
6.概括
什么是巴尔身体?
Barr body is the name given to the X chromosome that is inactive during the expression of the genes of somatic cells of females. Barr bodies are absent in normal males. Murray Barr discovered this inactive X chromosome in female somatic cells. Barr body is in the state of heterochromatin which is a transcriptionally inactive structure while the other copy, active X chromosome, is in the euchromatin state. Once the Barr body is packaged into heterochromatin, it is not easily accessible to molecules involved in transcription.
Since all females have two X chromosomes, X inactivation or lyonization is important in order to prevent them from having twice as many X chromosome gene products as males. In short, Barr body production ensures that only the necessary amount of genetic information is expressed in females, rather than doubling it. Therefore, throughout the cell’s whole life, one X chromosome of all somatic cells remains silent.
What is Polar Body?
In females, female gametes or eggs are produced by a process called oogenesis. Though this process starts during the embryonic development, the completion occurs after puberty. After puberty, every month, an ovum is produced. During the ovum production, three polar bodies are also produced at each cycle. Thus, polar bodies are the three haploid cells that result during the oogenesis process. They are not capable of undergoing fertilization with sperms.
Oogenesis begins from a diploid cell, and ovum production takes place via meiosis cell division. Meiosis I produces a primary oocyte and the first polar body. At fertilization, meiosis II process commences and produces a secondary oocyte, the second polar body and third polar body. At the end of meiosis, a mature oocyte (ovum) and three polar bodies are produced. Structurally, polar bodies are small cytoplasmic inclusion bodies containing a nucleus, ribosomes, Golgi, mitochondria and cortical granules.
What are the Similarities Between Barr Body and Polar Body?
- Barr body and polar bodies are found only in females.
- Both are important structures.
巴尔身体和极性身体有什么区别?
Barr体是女性体细胞细胞中的无活性X染色体,而极性体是卵子发生过程中的小单倍体细胞。因此,这是Barr身体和极性体之间的关键区别。此外,Barr体和极性体之间的另一个显着差异是,在X灭活过程中形成了Barr体,而在卵子发生过程中形成了极性。
Barr body formation is important in order to prevent females from having twice as many X chromosome gene products as males. Meanwhile, polar body formation indicates the completion of meiosis during the egg cell formation in a female. They are also used as tools for clinical diagnosis of human diseases and as metrics of embryonic potential. Furthermore, another difference between Barr body and polar body is the fate of each structure. Barr body remains inactive throughout the cells’ whole lifetime while polar body disappears or degenerates fast.
概括– Barr Body vs Polar Body
Barr body is the inactive X chromosome in female somatic cells. X inactivation maintains the expression of only the necessary gene products in females. Hence it prevents the doubling of X chromosome gene products in females compared to males. Meanwhile, the polar body is one of the three small haploid cells produced during the ovum production or the oogenesis. Polar bodies are not eligible for the fusion with sperm or fertilization. In short, the Barr body is an inactive chromosome in a female somatic cell while the polar body is a small haploid cell resulting during the oogenesis. So, this is the summary of the difference between Barr body and polar body.
Reference:
1. “Barr Body.” Biology Dictionary, 28 Apr. 2017,Available here.
2.“卵母细胞开发。”胚胎学,Available here.
Image Courtesy:
1.亨利·范迪克·卡特(Henry Vandyke Carter)的“ Gray5” - 这是一张修饰的图片,这意味着它已与原始版本进行了数字化更改。修改:矢量化(Coreldraw)。(公共领域)通过Commons Wikimedia
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