nondisjunction

简明释义

英[ˌnɒndɪsˈdʒʌŋkʃən]美[ˌnɑːndɪsˈdʒʌŋkʃn]

n. [遗] 不分离；不分开现象

英英释义

单词用法

同义词

反义词

例句

1.Results 64% of oocytes were normal, 36% of oocytes were aneuploidy, of which 22% were due to nondisjunction and 14% unbalanced predivision.

结果64%的卵细胞核型正常，36%的卵细胞为非整倍体，其中22%为同源染色体不分离，14%为姐妹染色单体非平衡性过早分离。

2.Results 64% of oocytes were normal, 36% of oocytes were aneuploidy, of which 22% were due to nondisjunction and 14% unbalanced predivision.

结果64%的卵细胞核型正常，36%的卵细胞为非整倍体，其中22%为同源染色体不分离，14%为姐妹染色单体非平衡性过早分离。

3.The geneticist explained that nondisjunction can lead to conditions like Down syndrome.

遗传学家解释说，非分离可能导致像唐氏综合症这样的疾病。

4.During meiosis, nondisjunction can result in gametes with an abnormal number of chromosomes.

在减数分裂过程中，非分离可能导致配子具有异常数量的染色体。

5.Research has shown that maternal age can increase the risk of nondisjunction during egg formation.

研究表明，母亲年龄的增加可能会提高卵子形成过程中发生非分离的风险。

6.In humans, nondisjunction can lead to trisomy or monosomy.

在人类中，非分离可能导致三体或单体。

7.The study focused on how nondisjunction affects embryonic development.

这项研究集中在非分离如何影响胚胎发育。

作文

Nondisjunction is a term that refers to the failure of homologous chromosomes or sister chromatids to separate properly during cell division. This phenomenon can occur during meiosis or mitosis, leading to an abnormal distribution of chromosomes in the resulting daughter cells. In the context of human genetics, nondisjunction (非分离) can have significant implications, often resulting in genetic disorders or conditions such as Down syndrome, Turner syndrome, and Klinefelter syndrome. Understanding nondisjunction is crucial for comprehending how these conditions arise and their impact on individuals and families.During meiosis, the process of cell division that produces gametes (sperm and eggs), nondisjunction can occur in either the first or second meiotic division. If it happens in the first division, homologous chromosomes fail to separate, leading to gametes with an abnormal number of chromosomes. If it occurs in the second division, sister chromatids do not separate, which also results in gametes with an incorrect chromosome number. When these abnormal gametes combine during fertilization, the resulting zygote may have an extra chromosome or be missing one, leading to aneuploidy.Aneuploidy is a condition where an individual has an abnormal number of chromosomes, which can lead to various developmental and health issues. For example, Down syndrome, caused by an extra copy of chromosome 21, is one of the most well-known consequences of nondisjunction (非分离). Individuals with Down syndrome may experience developmental delays, characteristic physical features, and increased risk for certain medical conditions. Turner syndrome, which affects females, occurs when there is a complete or partial absence of one of the X chromosomes, often resulting from nondisjunction during meiosis. Klinefelter syndrome, affecting males, is characterized by the presence of an extra X chromosome, also due to nondisjunction during gamete formation.The study of nondisjunction is not only important for understanding genetic disorders but also for exploring the mechanisms of cell division and the factors that can contribute to errors in this process. Research has shown that age, particularly maternal age, plays a significant role in the likelihood of nondisjunction occurring. As women age, the risk of chromosomal abnormalities in their eggs increases, which is why older mothers are more likely to have children with conditions like Down syndrome.In conclusion, nondisjunction (非分离) is a critical concept in genetics that explains the improper separation of chromosomes during cell division. Its implications are far-reaching, affecting not only the individuals who are born with aneuploidy but also their families and society as a whole. By studying nondisjunction, researchers can gain insights into the causes of genetic disorders and work towards better prevention and treatment strategies. Understanding this phenomenon helps us appreciate the complexity of human genetics and the delicate balance required for normal development.

非分离是一个术语，指的是同源染色体或姐妹染色单体在细胞分裂过程中未能正确分开。这种现象可以发生在减数分裂或有丝分裂中，导致子细胞中染色体的异常分布。在人类遗传学的背景下，非分离（nondisjunction）可能会产生重大影响，通常导致诸如唐氏综合症、特纳综合症和克氏综合症等遗传疾病或病症。理解非分离对于理解这些病症的产生及其对个人和家庭的影响至关重要。在减数分裂过程中，即产生配子（精子和卵子）的细胞分裂过程，非分离可以发生在第一次或第二次减数分裂中。如果它发生在第一次分裂中，同源染色体未能分开，导致配子中染色体数量异常。如果发生在第二次分裂中，姐妹染色单体未能分开，这也会导致配子中染色体数量不正确。当这些异常的配子在受精过程中结合时，结果形成的合子可能会有多余的染色体或缺少某个染色体，从而导致非整倍体。非整倍体是一种个体具有异常数量染色体的状态，这可能导致各种发育和健康问题。例如，唐氏综合症，由于第21号染色体的额外副本引起，是非分离（nondisjunction）最著名的后果之一。患有唐氏综合症的个体可能会经历发育迟缓、特征性身体特征和某些医疗条件的风险增加。特纳综合症影响女性，发生在一个X染色体完全或部分缺失的情况下，通常是由于减数分裂中的非分离引起的。克氏综合症影响男性，其特征是一条额外的X染色体，也由于配子形成过程中发生的非分离（nondisjunction）。研究非分离（nondisjunction）不仅对理解遗传疾病重要，而且对探索细胞分裂机制及可能导致这一过程错误的因素也至关重要。研究表明，年龄，特别是母亲的年龄，在非分离发生的可能性中扮演了重要角色。随着女性年龄的增长，她们卵子中染色体异常的风险增加，这就是为什么年长母亲更可能生出患有唐氏综合症的孩子。总之，非分离（nondisjunction）是遗传学中一个关键概念，解释了细胞分裂过程中染色体的不当分离。其影响深远，不仅影响出生时有非整倍体的个体，还影响他们的家庭和整个社会。通过研究非分离（nondisjunction），研究人员可以深入了解遗传疾病的原因，并努力制定更好的预防和治疗策略。理解这一现象帮助我们欣赏人类遗传学的复杂性以及正常发育所需的微妙平衡。