What evidence suggests that chimpanzee is more closely related to humans than other hominoid apes?

Options

A. DNA from sex chromoscomes only
B. Chromosome morphology only
C. Fossil remains
D. Banding pattern of autosomes

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for evidence that indicates chimpanzees are more closely related to humans than to other hominoid apes.

2. **Chromosome Count Comparison**: Humans have 46 chromosomes (23 pairs), while chimpanzees have 48 chromosomes (24 pairs). This initial difference in chromosome count is important for understanding genetic relationships.

3. **Chromosome Fusion**: It is crucial to note that human chromosome 2 is believed to be a fusion of two ancestral chromosomes (chromosome 12 and 13) found in chimpanzees. This suggests a close evolutionary relationship because it indicates a shared ancestry.

4. **Genetic Similarity**: Despite the difference in chromosome numbers, the genetic material (DNA) in the chromosomes of humans and chimpanzees is remarkably similar. This genetic similarity supports the idea that chimpanzees and humans share a more recent common ancestor compared to other hominoid apes.

5. **Bending Patterns of Chromosomes**: The bending patterns of chromosomes (autosomes) in humans and chimpanzees show significant similarities. These patterns are used in cytogenetics to identify chromosomal similarities and differences, providing further evidence of their close relationship.

6. **Conclusion**: The evidence from chromosome morphology, specifically the bending patterns of chromosomes and the fusion of chromosomes, suggests that chimpanzees are more closely related to humans than to other hominoid apes.