Meiosis and Genetic Diversity · 减数分裂与遗传多样性
| English | 中文 | Pinyin · 拼音 |
|---|---|---|
| crossing over/ˈkrɒsɪŋ ˈəʊvə/ | 交叉互换 | jiāo chā hù huàn |
| independent assortment/ˌɪndɪˈpendənt əˈsɔːtmənt/ | 自由组合 | zì yóu zǔ hé |
| genetic diversity/dʒɪˈnetɪk daɪˈvɜːsɪti/ | 遗传多样性 | yí chuán duō yàng xìng |
Why no two siblings are the same
- Brothers and sisters share the same parents, yet all look different.
- Sexual reproduction shuffles genes into brand-new combinations every time.
- Meiosis is where most of that shuffling happens.
- This variety is one of biology's greatest advantages.
为什么没有两个兄弟姐妹一样
- 兄弟姐妹有同样的父母,然而看起来都不同。
- 有性繁殖每一次都把基因洗成全新的组合。
- 减数分裂就是大部分这种洗牌发生的地方。
- 这种多样性是生物学最大的优势之一。
Crossing over
- During meiosis, matching chromosomes pair up closely.
- In crossing over 交叉互换, they swap sections of DNA.
- This mixes the mother's and father's genes on a single chromosome.
- Each chromosome that results is a new blend, unlike either parent's.
交叉互换
- 减数分裂期间,配对的染色体紧密地配在一起。
- 在交叉互换(crossing over)中,它们交换 DNA 的片段。
- 这把母亲和父亲的基因在同一条染色体上混合。
- 由此产生的每条染色体都是新的混合,不像任一亲本的。
In crossing over, what happens? · 在交叉互换中,发生了什么?
In crossing over, homologous chromosomes exchange matching sections, creating new gene combinations. · 在交叉互换中,同源染色体交换匹配的片段,创造新的基因组合。
Independent assortment
- Each pair of chromosomes lines up randomly before separating.
- This is independent assortment 自由组合.
- So each gamete gets a random mix of maternal and paternal chromosomes.
- With 23 pairs, that alone gives millions of possible combinations.
自由组合
- 每对染色体在分离前随机排列。
- 这就是自由组合(independent assortment)。
- 所以每个配子得到母方和父方染色体的随机混合。
- 光是 23 对,就给出数百万种可能的组合。
Where variation comes from · 变异从哪里来
Step through the ways meiosis and fertilization shuffle genes into new combinations. · 一步步走过减数分裂和受精把基因洗成新组合的各种方式。
Independent assortment · 自由组合 means… · 自由组合意味着……
Independent assortment · 自由组合: each pair orients randomly, so gametes get random mixes of maternal and paternal chromosomes. · 自由组合:每一对随机定向,所以配子得到母方和父方染色体的随机混合。
Random fertilization
- Any one of millions of sperm can fertilise the egg.
- This is random fertilization, multiplying the diversity again.
- Together, these three sources make each offspring genetically unique.
- All of this variety is the raw material for genetic diversity 遗传多样性.
随机受精
- 数百万个精子中的任何一个都能给卵子受精。
- 这是随机受精,再一次使多样性成倍增加。
- 这三个来源加在一起,使每个后代在基因上独一无二。
- 所有这些多样性就是遗传多样性(genetic diversity)的原材料。
Genetic diversity helps a population survive changing conditions. · 遗传多样性帮助一个种群在变化的条件下生存。
Variety means some individuals may cope with a new challenge — the raw material for evolution. · 多样意味着一些个体可能应对新的挑战——进化的原材料。
The random joining of any sperm with any egg is called random . · 任何精子与任何卵子的随机结合叫做随机。
Random fertilization multiplies the diversity already created within meiosis. · 随机受精使减数分裂中已经创造的多样性成倍增加。
Select all · 所有 sources of genetic diversity. · 选出遗传多样性的所有来源。
Cloning produces no · 否 diversity. The other three all shuffle genes into new combinations. · 克隆产生没有多样性。其余三种都把基因洗成新的组合。
Sexual reproduction creates diversity; asexual reproduction does not. A cell dividing by mitosis makes identical clones. Only meiosis, with crossing over and independent assortment, shuffles the genes to make every offspring different.
有性繁殖创造多样性;无性繁殖不会。一个通过有丝分裂分裂的细胞产生相同的克隆。只有减数分裂,连同交叉互换和自由组合,才把基因洗牌,让每个后代都不同。
Why a family is full of variety:
- Crossing over remixes each parent's chromosomes.
- Independent assortment deals each gamete a random hand of chromosomes.
- Random fertilization then pairs two unique gametes — so each child is a fresh combination, never seen before.
一个家庭为什么充满多样性:
- 交叉互换重新混合每个亲本的染色体。
- 自由组合给每个配子发一手随机的染色体。
- 随机受精随后把两个独特的配子配对——所以每个孩子都是一个全新的组合,从未见过。
Meiosis creates genetic diversity through three shuffling steps: crossing over (matching chromosomes swap sections), independent assortment (pairs line up randomly), and random fertilization (any sperm meets any egg). Together they make every offspring genetically unique — the raw material for evolution.
减数分裂通过三个洗牌步骤创造遗传多样性:交叉互换(配对的染色体交换片段)、自由组合(各对随机排列)和随机受精(任何精子遇上任何卵子)。它们一起让每个后代在基因上独一无二——进化的原材料。