Here’s a complete explanation of Homologous Chromosomes with appropriate labeled images to help you see and understand the concept clearly.
🧬 Homologous Chromosomes — With Images



📌 What the Images Show
- Pair of homologous chromosomes: Two chromosomes of similar shape/size (one from each parent) shown side by side.
- Diagram of homologous pairing and crossing-over: Shows how non-sister chromatids can exchange genetic material in meiosis.
- Detailed structure with sister chromatids: Each duplicated chromosome has two sister chromatids.
🧠 English Explanation
Definition
Homologous chromosomes are paired chromosomes in a diploid cell that:
-
Have the same genes at the same positions (loci)
— even if the versions (alleles) may differ. (Wikipedia)
-
Are similar in size and shape
They align with each other during meiosis. (khanacademy.org)
-
Come as one from each parent
In humans, cells typically have 23 homologous pairs (46 total chromosomes). (ThoughtCo)
How They Appear
- Each homologous chromosome is a single chromosome before DNA replication.
- After DNA replicates, each one consists of two identical sister chromatids joined at a centromere.
Importance in Meiosis
- Homologous pairs pair up (synapsis) in meiosis I. (Biology LibreTexts)
- During this pairing, crossing over can occur — where non-sister chromatids exchange DNA. This creates genetic variation in gametes. (Genomics Education Programme)
🈶 中文解释(Chinese Explanation)
定义:什么是同源染色体
同源染色体 是二倍体细胞中 成对出现 的染色体:
-
在 相同位置(基因座)上有相同的基因,
但这些基因可能是不同形式(等位基因)。 (Wikipedia)
-
它们 大小、形状、带纹很相似。 (khanacademy.org)
-
每对染色体中,一条来自母亲,一条来自父亲。 (ThoughtCo)
它们的外观
- 在 DNA 复制之前,每一条是单一染色体。
- 复制后,每条都变成 两个姐妹染色单体(sister chromatids),通过 着丝点 连接起来。
在减数分裂中的角色
🧩 Key Features of Homologous Chromosomes
| Feature | English | 中文 |
| ------------------- | -------------------------------- | ---------------- |
| Pair of chromosomes | Same genes, same positions | 含有相同基因且位置一致的染色体对 |
| Origin | One from mother, one from father | 来自父母双方各一条 |
| Replication | Becomes two sister chromatids | 复制后形成两个姐妹染色单体 |
| Role in meiosis | Pairing & crossing-over | 在减数分裂中配对并发生交叉互换 |
| Genetic variation | Increased by crossing-over | 由交叉互换增加遗传多样性 |
If you want, I can also show you diagrams of meiosis I focusing on homologous chromosome behavior, or a labeled worksheet style diagram in both English and Chinese!