Page 67 - Biology - XII

A. Comments (Fig. 11.13)
1. It is the pedigree of colour-blindness.

2. The mother is colour-blind and father is normal.
3. The children of such parents are: male colour-blind and female is carrier.
4. The grandchildren of such parents (P ) are: male colour-blind and normal, female colour-blind
1
and carrier.

P 1 Colour blind male

Normal female
F
1 Carrier female

Normal male

Fig. 11.14: Marriage of colour blind male (father) and normal female (mother).

The daughter is carrier and transmits the trait to next generation—males colour-blind and normal, females
carrier and normal.
B. Comments (Fig. 11.14)

1. This is the pedigree for colour-blindness.
2. The father is colour-blind and mother is normal.
3. The children of such parents are: male is normal and female is carrier.
4. The grandchildren of such parents are: males colour-blind and normal, females carrier and normal.

VIVA VOCE

Q1. If a gene is present on the autosome, will it eff ect the transfer of trait to one sex?
Ans. No, as it is present on the autosome, it will eff ect both the sexes equally.

Q2. Human males and females are equally aff ected for a trait. What do you interpret?
Ans. The gene coding the trait is present on autosomes.
Q3. Mention the genotype of a carrier for fused earlobes.
Ans. Aa

Q4. Study this fi gure for the inheritance of the fused earlobes. What is the
aa AA probability of the fused earlobes in this case?

Ans. 1 (one)

Q5. Would you like to know about your spouse regarding such trait?
Ans. Yes
Q6. What does the vertical line represent in the pedigree chart?
Ans. Descendants/children produced

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