Holandric genes are always transfer from father to..........

Answer

**Step-by-Step Solution:**

1. **Understanding Holandric Genes**: Holandric genes are defined as genes that are located exclusively on the Y chromosome. This means they are present only in males, as females do not possess a Y chromosome.

2. **Inheritance Pattern**: Since holandric genes are found on the Y chromosome, they are inherited from father to son. This is because only males have a Y chromosome to pass on to their offspring.

3. **Sex Chromosomes**: In humans, males have one X and one Y chromosome (XY), while females have two X chromosomes (XX). The Y chromosome carries specific genes that are not present on the X chromosome.

4. **Conclusion**: Therefore, holandric genes are always transferred from father to son, as only males can inherit the Y chromosome from their fathers.

5. **Example**: An example of a holandric trait is facial hair growth, which is influenced by genes located on the Y chromosome.

**Final Answer**: Holandric genes are always transferred from father to son.

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