IO	IO
IA	IAIO (A blood group)	IAIO (A blood group)
IB	IBIO (B blood group)	IBIO (B blood group)

Genotypes of blood group A are IAIA or IAIA and B are IBIB or IBIO. Answer : (c)

Genetically identical progeny can be produced if genes which carry same character property. This can happens when individual produces identical gametes. Answer : (b)

Variation are differences in morphological, physiological, cytological and behavioristic trait of individuals belonging to same species. They appear in offsprings due to:- (i) Reshuffling of genes/chromosomes by chance separation of chromosomes. They occurs during independent assortment. (ii) Crossing over: Chromosomal crossover, or crossing over, is the exchange of genetic material during sexual reproduction between two homologous chromosomes' non-sister chromatids that results in recombinant chromosomes. (iii) Chance combination of chromosomes during meiosis and fertilization. Answer : (b)

Gametes	R	r
R	RR (red flower)	Rr (pink colour)
R	RR (red flower)	Rr (pink colour)

In Mirabilis jalapa, Red flower (RR) is crossed with white flower (rr) which produces hybrid Pink colour flower (Rr). Pink colour flower (Rr) × Red colour flower (RR) Red flower : pink flower = 2 : 2 Answer : (b)

Gametes	R	r
R	RR (red)	Rr (red)
r	Rr (red)	Rr (white)

Offspring obtained has ratio red flower : white flower = 3 : 1. This implies that recessive trait i.e. white has appeared in the progeny. This occurs when both the parent are heterozygous with dominant character. Thus genotype of both parent is Rr ( heterozygous) . Rr (red flower) × Rr (red flower) Answer : (b)

Gregor Johann Mendel appropriately known as father of genetics, proposed the theory of inheritance. Hugo de Vries is Father of Mutation theory of evolution. Darwin is known as father of evolution. Morgan and his colleagues confirmed the chromosomal theory of inheritance. Answer : (b)

	IB	IO
IA	IAIB (AB blood group)	IAIO (A blood group)
IO	IBIO (B blood group)	IOIO (O blood group)

Answer : (b)

Phenotypic ratio in F2 progeny of incomplete dominance is same as genotypic ratio Ratio= 1 : 2 : 1 Answer : (c)

Gametes	CP	Cp	cP	cp
CP	CCPP (purple)	CCPp (purple)	CcPP (purple)	CcPp (purple)
Cp	CCPp (purple)	CCpp (white)	CcPp (purple)	Ccpp (white)
cP	CcPP (purple)	CcPp (purple)	ccPP (white)	ccPp (white)
cp	CcPp (purple)	Ccpp (white)	ccPp (white)	Ccpp (white)

Sweet pea (Lathyrus odoratus) is an example of complementary genes. Here, the flower colour is purple if dominant alleles of two genes C and P are present together. The colour is white if the double dominant condition is absent. CcPp × CcPp → Purple : white = 9 : 7 So, White colour not appear in the previous generation, reappears in the next generation. It is called Law of segregation. Answer : (d)

Word genetics comes from the word gene. The term was coined and used for the first time by W. Bateson(1905). Answer : (d)

Albinism is an autosomal genetic recessive disorder. The gene for albinism is a. It does not produce the enzyme tyrosinase but is produced by normal allele A . Thus only homozygous individuals (aa) are affected. Both the parents are albino, it means their alleleic pair is aa. Then all the progeny will also have genotype aa i.e., they will be albino. Answer : (a)

Gametes	T	T
T	TT	TT
t	Tt	Tt

Tt (heterozygous tall plant) × TT ( homozygous tall plant) F2 generation All the offsprings are tall plants with 50% homozygous and 50% heterozygous Answer : (b)

Recessive trait (blue eye) is expressed in progeny. This occurs when parents has heterozygous allele expressing dominant trait. Thus genotype of parents are Bb. Answer : (a)

Blood group O has genotype IOIO. One allele is obtained from mother and one from father. That means one of the IO is obtained from father. Father has B blood group. So phenotype can be IBIB or IBIO. So correct genotype of this case will be IBIO Answer : (d)

While Mendel's work laid the foundation, it was German botanist Carl Correns (1864–1933) who is credited with the actual discovery of incomplete dominance. Answer : (a)

Gametes	T	t
t	Tt	tt
t	Tt	tt

Tt (heterozygous tall plant) × tt ( homozygous dwarf plant) F2 generation 50% are heterozygous tall plant and 50% are recessive dwarf plant. Answer : (b)

Number of gametes = (2)n where n= number of heterozygous allele. Here n=1. No. of gametes = 2 Answer:(a)

No. of traits (n)	Experiment	Types of gametes (2n)	No. of offsprings (gametes)2	No. of phenotype (2n)	No. of genotype (3n)	Phenotypic ratio	Genotypic ratio
3	Trihybrid cross	8	64	8	27	(3:1)3	(1:2:1)3

Answer : (a)

A pair of contrasting characters is called allelomorph or allele. Answer : (a)

One allele is dominant over other. In F1 generation the dominant phenotype appears, the recessive reappears in F2 generation. Since red is dominant over white, all offspring produced will be plants having red flower. Answer : (c)

Gametes	TY	Ty	tY	ty
TY	TTYY	TTYy	TtYY	TtYy
Ty	TTYy	TTyy	TtYy	Ttyy
tY	TtYY	TtYy	ttYY	ttYy
ty	TtYy	Ttyy	ttYy	ttyy

Tall F2 progeny = 12/16 Answer : (c)

No. of chromosomal composition that can be prepared is derived by formula 2n where n is number of homologous pair of chromosomes. In Pisum sativum, there are 14 chromosomes. Number of homologous pair will be 7. No. of composition is 27. Answer : (b)

When two genes are close together on the same chromosome, they do not assort independently and are said to be linked. Whereas genes located on different chromosomes assort independently and have a recombination frequency of 50%, linked genes have a recombination frequency that is less than 50%. The linked genes tend to get inherited together. The link between them fails to break. Genes whose loci are nearer to each other are less likely to be separated onto different chromatids during chromosomal crossover, and are therefore said to be genetically linked. In other words, the nearer two genes are on a chromosome, the lower is the chance of a swap occurring between them, and the more likely they are to be inherited together. Answer : (a)

In 1868 Charles Darwin proposed Pangenesis, a developmental theory of heredity. He suggested that all cells in an organism are capable of shedding minute particles he called gemmules, which are able to circulate throughout the body and finally congregate in the gonads. Answer : (c)

Blood group is determined by antigen. An antigen is any substance that causes your immune system to produce antibodies against it. Blood group O does not have antigen A and antigen B. Thus they can carry both anitbodies Anti-A and Anti-B in their serum. Rh- does not carry Rh antigen and thus can carry anitbodies. So, correct answer O and Rh-. Answer : (a)

Crossing of F1 individual having dominant phenotype with its homozygous recessive parents is called test cross. The test cross is used to determine whether the individuals exhibiting dominant characters are homozygous or heterozygous. Answer : (b)

Traits	Dominant	Recessive
Plant height	Tall (1.2 – 2.0m)(T)	Dwarf (0.25 – 0.5m) (t)
Flower position	Axillary (A)	Terminal (a)
Pod colour	Green (G) or (Y)	Yellow (g) or (y)
Pod shape	Full or inflated (I) or (C)	Constricted (i) or (c)
Flower colour	Violet (V) or (W)	White (v) or (w)
Seed shape	Round (R) or (W)	Wrinkled (r) or (w)
Seed colour	Yellow (Y) or (G)	Green (y) or (g)

Answer : (b)

Sickle cell anemia is caused by the substitution of Glutamic acid (Glu) by Valine (Val) at the sixth position of the beta globin chain of the haemoglobin molecule. The substitution of amino acid in the globin protein results due to the single base substitution at the sixth codon of the beta globin gene from GAG to GUG. The mutant haemoglobin molecule undergoes polymerisation under low oxygen tension causing the change in the shape of the RBC from biconcave disc to elongated sickle like structure. Answer : (b)

Law of dominance: When a pair of alleles are bought together in F1 hybrid, then only one of them expresses itself, masking the expression of other completely. Allele is dominant if it is expressed in both homozygous and heterozygous condition. Answer : (a)

Variation are differences in morphological, physiological, cytological and behavioristic trait of individuals belonging to same species. They appear in offsprings due to:- (i) Reshuffling of genes/chromosomes by chance separation of chromosomes. They occurs during independent assortment. (ii) Crossing over: Chromosomal crossover, or crossing over, is the exchange of genetic material during sexual reproduction between two homologous chromosomes' non-sister chromatids that results in recombinant chromosomes. (iii) Chance combination of chromosomes during meiosis and fertilization. Answer : (a)

The offspring has blood group genotype IAi. IA is dominant over i. the blood group is A. Answer : (a)

No. of traits (n)	Experiment	Types of gametes (2n)	No. of offsprings (gametes)2	No. of phenotype (2n)	No. of genotype (3n)	Phenotypic ratio	Genotypic ratio
2	Dihybrid cross	4	16	4	9	9:3:3:1	2:4:2:1:2:1:1:2:1

Answer : (b)

Biometrical genetics is the science concerned with the inheritance of quantitative traits. Answer : (d)

Mendel has three laws: (i) Law of dominance (ii) Law of segregation and last (iii) Law of independent assortment. Answer : (c)

gamete, is a cell containing only one set of dissimilar chromosomes, or half the genetic material necessary to form a complete organism (i.e., haploid). There are two set of allele G and g, L and l. Gametes can have only half of the allele. So correct option is Gl Answer : (d)

Hybrid vigour or heterosis is the superiority of hybrid over either of its parents in one or more traits. An offspring is heterotic if its traits are enhanced as a result of mixing the genetic contributions of its parents. Hybrid vigour is directly proportional to the strength of heterozygosity. Answer : (d)

At the time of formation of gametes, these two factors obviously separate or segregate. A gamete may either carry either the dominant or the recessive factor but not both. Answer : (d)

Sickle cell anemia is an inherited genetic condition in which afflicated individuals contain red blood cells that under low oxygen tension become elongated and curved. Because of the shape, sickled cells clump together, and blood becomes more viscous. The result is slowing of flow, even greater loss of oxygen from the haemoglobin. Answer : (d)

Non-inherited variants occur at some time during a person's life and are present only in certain cells, not in every cell in the body. Because non-inherited variants typically occur in somatic cells (cells other than sperm and egg cells), they are often referred to as somatic variants. Answer : (c)

Color blindness is determined by a sex-linked recessive allele found on the X chromosome. Oculocutaneous albinism is inherited in an autosomal recessive pattern , which means both copies of a gene in each cell have mutations. Hemophilia A and hemophilia B are inherited in an X-linked recessive pattern. The Rh-positive gene is the dominant gene when paired with an Rh-negative gene. Answer : (d)

Gametes	RY	Ry	rY	ry
RY	RRYY	RRYy	RrYY	RrYy
Ry	RRYy	RRyy	RrYy	Rryy
rY	RrYY	RrYy	rrYY	rrYy
ry	RrYy	Rryy	rrYy	rryy

F2 generation 1RRYY, 2RRYy, 2Rryy, 4RrYy Answer : (a)

	IO	IO
IA	IAIO (A blood group)	IAIO (A blood group)
IB	IBIO (B blood group)	IBIO (B blood group)

Mother has O blood group. Genotype is IOIO. Father blood group is AB. Genotype is IAIB. The child will have either A blood group or B blood group. Mother is true but father claimed is wrong. She cannot sue the wrong person. Answer : (d)

Traits	Dominant	Recessive
Plant height	Tall (1.2 – 2.0m)(T)	Dwarf (0.25 – 0.5m) (t)
Flower position	Axillary (A)	Terminal (a)
Pod colour	Green (G) or (Y)	Yellow (g) or (y)
Pod shape	Full or inflated (I) or (C)	Constricted (i) or (c)
Flower colour	Violet (V) or (W)	White (v) or (w)
Seed shape	Round (R) or (W)	Wrinkled (r) or (w)
Seed colour	Yellow (Y) or (G)	Green (y) or (g)

Answer : (c)

Blood group A has genotype IAIO and IAIA. Antigen produced is A and it produces antibodies Anti- A also known as (b) antibodies. Due to its genotype, it can donate to blood group A and blood group AB person. Blood group A person can be a parent to Child with blood group if the other parent has Blood group of B or AB. In the above options, option (a) is correct. Answer : (a)

The proteins present on the surface of Red blood cells are called Antigens. They induce a specific immune response and induce the formation of specific antibodies against it. Answer : (c)

Gametes	CP	Cp	cP	cp
CP	CCPP (purple)	CCPp (purple)	CcPP (purple)	CcPp (purple)
Cp	CCPp (purple)	CCpp (white)	CcPp (purple)	Ccpp (white)
cP	CcPP (purple)	CcPp (purple)	ccPP (white)	ccPp (white)
cp	CcPp (purple)	Ccpp (white)	ccPp (white)	Ccpp (white)

Sweet pea (Lathyrus odoratus) is an example of complementary genes. Here, the flower colour is purple if dominant alleles of two genes C and P are present together. The colour is white if the double dominant condition is absent. CcPp × CcPp → Purple : white = 9 : 7 Answer : (d)

No. of traits (n)	Experiment	Types of gametes (2n)	No. of offsprings (gametes)2	No. of phenotype (2n)	No. of genotype (3n)	Phenotypic ratio	Genotypic ratio
3	Trihybrid cross	8	64	8	27	(3:1)3	(1:2:1)3

There are 3 traits involved. Thus, this is a trihybrid cross. Answer : (c)

Etiolation is a process in flowering plants grown in partial or complete absence of light. It is characterized by long, weak stems; smaller leaves due to longer internodes; and a pale yellow color. The development of seedlings in the dark is known as "skotomorphogenesis" and leads to etiolated seedlings. An albinism is a group of inherited disorders characterised by little or no melanin production. Answer : (c)

No. of traits (n)	Experiment	Types of gametes (2n)	No. of offsprings (gametes)2	No. of phenotype (2n)	No. of genotype (3n)	Phenotypic ratio	Genotypic ratio
2	Dihybrid cross	4	16	4	9	9:3:3:1	2:4:2:1:2:1:1:2:1

Answer : (a)

Gametes	RY	Ry	rY	ry
RY	RRYY	RRYy	RrYY	RrYy
Ry	RRYy	RRyy (green)	RrYy	Rryy (green)
rY	RrYY	RrYy	rrYY	rrYy
ry	RrYy	Rryy (green)	rrYy	Rryy (green)

RRYY (Round, yellow seed) and × rryy(wrinkled, green seed) Green F2 progeny = 4/16 Answer : (c)