PRINCIPLES OF INHERITANCE AND VARIATION
2. A poultry farm manager was cursing his hens for producing lion share of cocks in its progeny. Hearing this, Kumar-farm attender starts to blame his wife for delivering consecutive girl children. Analyze the situations scientifically and state whether you agree with Kumar. (3)
1. In the given pedigree the shaded figures denote individuals expressing a specific trait. (1)
Which of the following is the most probable mode of inheritance of the trait?
A. Simple Mendelian recessive
B. Co-dominant relationship of a single pair of alleles.
C. X-linked recessive transmission
D. X-linked dominant transmission
E. Polygenic inheritance
2. A specific rat population was controlled for about a decade by a poison. After a population decline for about 10 years, the rat population was increased and stabilized.
Resistance to poison is governed by a dominant autosomal gene ‘R’. In 1975 majority of the resistant animals are heterozygous at this locus (Rr).
a. What was the major genotype of the rat population before 1961? (1)
A) RR B) Rr C) rr D) R is absent as it is produced by a mutation.
b. What explanation you give for the development of resistance against the poison in these rats? (1)
c. “This illustration can be utilized to explain the Theory of Evolution.” Substantiate. (1)
1. Explain the phenomenon shown in the following figure and the reason for difference in the production of recombinants in cross A and cross B as explained by Morgan. (3)
Difference in chromosome number of some human beings A, B, C and D are given below:
A. 22 pairs of Autosomes
B. 22 pairs of autosomes + XO
C. 22 pairs of autosomes + 1 autosome
D. 22 pairs of autosomes + XXY
a) Identify the person who suffers from Klinfelter’s syndrome. Write its symptoms.
b) Differentiate between aneuploidy and polyploidy. (3)
2. “Gopalan argues that if father is of ‘A’ blood group, mother is of ‘B’ blood group. Their children can only be ‘A’ group, ‘B’ group or ‘AB’ group.”
a. Do you agree with Gopalan’s argument?
b. Give reason for your answer. (2)
1. Correct the sequence of sickle cell hemoglobin. (1)
2. Identify the syndrome from the genotype given below:
a. 44 autosomes + XXY
b. 44 autosomes + XO (1)
3. Sex of the baby is determined by the father, not by the mother. Substantiate. (2)
4. (a) Define mutation. (1)
(b) What are the different types of mutation? (1)
5. The family of Queen Victoria shows a number of haemophilic descendants as she was the carrier of the disease. Name the pattern of inheritance of this royal disease. (1)
a. Identify the syndrome from the diagram and write the genotype.
b. It occurs in both sexes (male & female). Write the reason. (2)
2. Fill in the blanks:
a. ………………. is a metabolic disorder that occurs due to the lack of an enzyme, that converts phenylalanine to tyrosine.
b. ……………… is a disease caused by the substitution of Glutamic acid by Valine at 6th position. (1)
3. It is evident that, it is the genetic make-up of the sperm that determine the sex of the child in human beings. Substantiate. (2)
1. Diagrammatic representation of the pedigree analysis of the inheritance of sickle cell anaemia is shown below: (3)
a. Name the type of inheritance shown in the figure.
b. Write the genotype of A & B. (Hint: Disease is controlled by a pair of alleles HbA & HbS)
c. Represent pedigree analysis of an X-linked recessive inheritance diagrammatically.
2. Observe the inheritance shown in A and B.
a. Name the type of the inheritance shown in A and B.
b. What is the difference between the two types of inheritance? (2)