二倍体

二倍体定义

二倍体
adj。,n。,[dəpləd]
Definition: having two sets of each chromosome

二倍体Definition

让我们先了解这个词的含义 -二倍体。From the words ‘d一世',意思是“二”,和'倍增'T.hat refers to the number of sets of染色体在一个cell,这个术语被定义为拥有两组每种染色体的

单倍体与二倍体
图1:单倍体与二倍体

二倍是什么意思?In genetics and biology, the term diploid refers to the cell containing two sets of homologous chromosomes wherein each chromosome in a set is obtained from each of the two parent cells. So you might be wondering,what are homologous chromosomes?嗯,染色体基本上是DNA那包装了一些蛋白质。和同源染色体是具有相似或相应的染色体基因对于某些特征。在人类,在每个遗传轨迹,存在基因变体(等位基因),并且这些变体已经从父母继承。
The majority of the plants and animals are made up of diploid cells except for their sex cells or the gametes that are单倍体。单倍体细胞包含的细胞一组染色体在里面Nucleus。两倍单倍体性细胞的融合导致组倍体细胞的形成Zygote.

什么是二倍体?A diploid cell is a cell that contains a diploid chromosome number, meaning the cell has two sets (or two copies) of homologous chromosomes in the nucleus.那么,多倍体细胞有多少染色体?如果单倍体细胞有'N'染色体数量,然后是二倍体的数字是'2N’.

在人类中,有两种类型的细胞:体细胞(体)细胞和性别细胞。体细胞是二倍体的;因此,体细胞可以被认为是二倍体细胞的同义词。

二倍体(biology, genetics definition):(1)Noun,一种cell或者生物consisting of two sets of染色体where one set comes from the mother and another set from the father; (2)形容词,of, or pertaining to, a diploid, that is a cell or an organism with two sets of chromosomes.词源: from Greek diplous, meaning double + -oid.Derived term:二倍体y比较:多倍体单倍体

倍性:单倍体,二倍体和多倍体

术语 '倍增'是指在细胞中存在的染色体组的数量,其由'n'表示。因此,细胞可以基于作为单倍体,二倍体和单倍体的染色体组数分类多倍体(see Table 1). Cells that possess three or more sets of chromosomes are referred to as polyploids. Quite interestingly, ploidy can be as high as 64 sets (Tetrahex contaploid.);卵虫报告了高达10,48,576个倍增性的倍增性!在人类中,多倍体通常是致命的,通常,在妊娠早期期间自然地中止多倍体胎儿。人类的多倍体可能是由于额外染色体的缺失或外观,这是一种称为一个非倍性。在人类中看到的最常见的短倍性是三重子其中存在额外染色体的外观。唐氏综合症(三重奏21),佩特综合征(三术13)和Edwards综合征(三术18)是人类中的一些共同的三族条件。另一方面,缺失的染色体导致monosomy。Turner syndrome is a common type of monosomy wherein a female has a missing or damagedX染色体。在动物(特别是更高的动物)中很少看到多倍体。它在植物中更常见。土豆 (Solanum Tuberosum.),非洲爪青蛙(Xenopus laevis.)和平原Viscacha大鼠(tympanoctomys barrerae.或红色vizcacha大鼠)是多倍体的实例。

Table 1: Classification of cells based on the number of chromosomes

倍增 Chromosomes 表示 Class
单倍体 一set of chromosome N 单倍体
二倍体 二sets of chromosomes 2N 二倍体
三倍体 三套染色体 3N. Polyploidy
tetraploid. Four sets of chromosomes 4n
Pentaploid. Five sets of chromosomes 5.N
Hexaploid. Six sets of chromosomes 6n
七倍体 Seven sets of chromosomes 7n

different ploidies diagram
图2:不同族的示意图:单倍体,二倍体和多倍体(例如三倍体和四倍体)

人类二倍体细胞中有多少染色体?什么类型的细胞是二倍体?The chromosomal diploid number in humans is 46 (i.e. 2n=46 chromosomes or 23 pairs of chromosomes). All the body cells like, blood cells, skin cells, muscle cells are diploid. Only sex cells or gametes are not diploid; sex cells are haploid. In that case, one must be curious to know how many chromosomes does a sex cell contains? Human sex cells or the gametes are haploid, and hence, contain n=23 chromosomes. This sentence, thus, clarifies a common query:人体配子单倍体或二倍体吗?
在人类中,性别细胞是鸡蛋(女性性细胞)和精子细胞(男性性细胞)。每种单倍体性细胞含有n = 23染色体。在施肥时,精子细胞单元与蛋细胞形成二倍体子宫(2n = 46)。这是至关重要的,因此人体内部细胞内的染色体的总数保持恒定在46和T.他的染色体数量可以在人代中保持不变。

Schematic representation of a sperm cell fertilizing an ovum
Figure 3: Schematic representation of a sperm cell fertilizing an ovum

To have half the number of chromosomes, the haploid sex cells are produced by the process ofmeiosis为了保留染色体的数量,因为它是单倍体性细胞在施肥期间联合,以形成具有两组染色体的单个细胞。并且从该二倍体单细胞中,通过有丝分裂细胞分裂会出现更多的二倍体细胞,形成多细胞体体。

减数分裂是细胞分裂的过程,其中每个含有四个子细胞的含有染色体数量的一半存在于母细胞中。相反,在有丝分裂中,细胞分裂的产物是含有相同数量的染色体的两个子细胞。下图可以有助于在相对于单倍体和二倍体细胞上描绘两种细胞分裂之间的差异。
有趣的是,雄性蜜蜂,黄蜂和蚂蚁等生物是从未受精,单倍体卵产生的,因此,它们是单倍体生物。

MeIosis与丝分裂图
图4:不同倍性由于不同的泰pes of cell division namely, meiosis and mitosis. Source: Modified by Dr. Amita Joshi ofBiologyOnline.com从图中创建的图表
Whatisdna.net.

基于这些,我们现在可以区分单倍体细胞和二倍体细胞;表2表示单倍体和二倍体细胞之间的差异。

表2:单倍体与二倍体细胞之间的差异

单倍体 二倍体
A cell that possesses only one set of chromosomes 具有两组染色体的细胞
这些细胞是由于减数分裂细胞分裂产生的 有丝分裂导致二倍体细胞的形成
在人类中,只有性细胞或配子是单倍体细胞 在人类中,除了性别细胞之外的所有细胞都是二倍体。这些也称为体细胞
由于减数分裂期间交叉的过程,单倍体细胞没有遗传上与母细胞相同 二倍体细胞是遗传上,由于有丝分裂细胞分裂,父母细胞的精确复制品。
Examples- Female gamete- ovum/egg; Male gamete- sperm 实例 - 肌肉细胞,皮肤细胞等

二倍体的例子

在人类中,二倍体细胞或2N = 46(或23对染色体),在狗中,在蚯蚓中,2n = 78(或39对染色体),2n = 36(或18对染色体)和大肠杆菌,2n = 1。在整个生命跨度跨越二倍体的动物仍然存在;然而,许多植物可以将它们的倍性状态从单倍体到二倍体改变它们的倍性状态,反之亦然。两个倍率阶段之间的这种变化现象称为世代的交替。植物循环的二倍体阶段被称为sporophytic stagewhereas the haploid stage of life is known as the杂草阶段。在植物群中,包括蕨类植物的蕨类植物主要在植物跨度中主要是孢子体阶段。

生成交替的示意图
图5:生成交替的示意图。来源:CNX OpenStax.,cc by-sa 4.0

有趣的是,病毒(如含有两个RNA拷贝的人泡沫状病毒,人T型淋巴细胞和HIV)也称为二倍体颗粒。

子系统的生物重要性

倍增level is the determinant of the number of mutations that arise in an individual. Accordingly, a higher number of mutations arise in diploids in comparison to the haploids, as diploids have double the number of mutational targets. However, the utility or the lethality of the mutation is determined by the fitness of the organism and the rate of change in its environmental conditions. In case an organism is not well adapted to its environment or is present in a challenging environment, diploids will have better survival and adaptability rate in comparison to the haploids. However, the evolution process is also critically dependent on the fate of these mutations and their selective effects. In the case of haploids, every mutation, lethal or valuable, would be expressed immediately. Although, mutations become apparent among diploids when they are in heterozygous form. It is important to note that deleterious mutations are more eliminated more efficiently eliminated in haploids than in diploids. Similarly, the probability of retaining a favorable mutation is higher in haploids (~2 s) than in diploids (~2hs). Thus, based on these concepts, diploid organisms are well adapted for changes when evolutionary changes are controlled by mutation, while haploid organisms are well equipped for evolutionary changes when evolutionary changes are controlled by selection.

What is diploid? How many chromosomes are in a human cell? 倍增是指一个基因组中的同源染色体组的数量cell或者生物。每组都被指定N。The term diploid refers to a cell or an organism that has two sets of chromosomes. In humans and other higher forms of living things, one of the two sets is derived from the mother’s gamete and the other is from the father’s gamete. The chromosomes from the two gametes have come together during施肥。In a diploid state, the单倍体数字 (N)加倍,因此,这种情况是由2NAn example of a cell in a diploid state is a躯体 cell。在人类中,体细胞通常含有46 chromosomes与人单倍体相反配子(鸡蛋和精子细胞)只有23染色体

If you want to learn more about polyploidy, read our tutorial:Polyploidy

参考

  • Favier,&Maitre(1965)。les cellulesdiploïdes贪婪[人类二倍体细胞]。Revue des Corps de Sante des Armes Terre,Mer,Air,6(2),227-236。
  • Aaronson, S., & Todaro, S. (1969). Human diploid cell transformation by DNA extracted from the tumor virus SV40. Science (New York, N.Y.), 166(3903), 390–391. https://doi.org/10.1126/science.166.3903.390
  • 李,Y.,&Shuai,L.(2017)。多功能遗传工具:单倍体细胞。干细胞研究与疗法,8(1),197. https://doi.org/10.1186/s13287-017-0657-4。
  • Pearson J.(1992)。改变质量控制问题:二倍体和非二倍体细胞系。生物标准化的发展,76,13-​​17。

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1.二倍体细胞中有多少套染色体?
2.哪些细胞是二倍体?
3.受精,所得到的细胞(Zygote)是......
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在血管植物中,孢子体是......

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