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Dr. sahu’s aipmt biology Classes
( no.-1 ; biology tuition of Chhattisgarh )
numeriCal of genetiCs
Q.1. Yellow , wrinkled when crossed yellow , wrinkled produce 115 yellow, wrinkled and 35 green
wrinkled. Give th genotype of parents.
Q.2. In man , assume that brown eyes(B) are dominant over blue-eyes(b) and right handness (L) is dominant
over left handness ( l ) . A brown – eyed, right handed man marries a blue-eyed, right handed woman,
and their first child is blue eyed and left handed. What are the genotype of the two parents?
Q.3. In tomato, red fruit ( R ) is dominant over yellow fruit ( r ); and spherical shape (S) is dominant over
cylindrical shape (s). the two allelic pairs are inherited independently. A cross between red spherical
and red cylindrical gave 122 red spherical; 120 red cyndrical; 39 yellow spherical and 41 yellow
cylindrical. Determine the genotype of parents?
Q.4. In Cattle , hornless condition ( P ) is dominant over horned (p) .
In certain bull is bred to three cows. With cow A which is horned, a hornless calf is produced;
with cow B also horned, a horned calf is produced; with cow C which is hornless , a horned calf is
produced. What are the genotypes of the four parents?
Q.5. A woman has a rare abnormality of the eyelids called ptosis, which makes it impossible for her to mopen
her eyes completely.This condition has been found to depend on a single dominant gene( P ). The
woman’s father had ptosis, but her mother had normal eyelids. Herfather’s mother had normal eyelids.
[a] what are the probable genotypes of the woman, her father and mother? [b] What proportion of her
children will be expected to have ptosis if she marries a man with normal eyelids?
Q.6. Purple flower colour in pea plant ( Lathyrus ) is produced as a result of interaction between two pairs of
genes C and P . If a purple flowered pea plant is crossed with a white flowered; they produced 14
puple and 16 white. Give the probable genotype of the parents?
Q.7. Mating between black rodents of the same genotype produed ofsprings in the ratio of 15 cream
coloured; 45 black and 19 albino.give the genotype of parents?
Q.8. When dogs from a true breeding brown coat line were mated to dogs from a true breeding white coat
line , all F-1 progeny were with white coat colour, Brother and Sister mating of F-1 progeny produced
F-2 phenotypes in the ratio of 130 white : 35 black : 11 brown. Give the genotype of parents?
Q.9. A homozygous yellow rat when mated with a homozygous black rat, produced F-1 all grey in
colour.Brother-sister mating of F-1 produced F-2 progeny in the phenotypic ratio of 27 grey : 9 yellow :
8 black : 3 cream coloured. Give the genotype of parents?
Q.10. A rose comb crossed to a walnut comb produced offsprings in the ratio of 15 walnut : 15 rose : 5 pea :
5 single.Determine the genotype of parents?
Q.11. A rose comb crossed to a pea comb comb produced 19 walnut and 20 rose offsprings.determine the
genotype of parents?
Q. 12. In tomato, genotype aabbcc produced 100 gm. Tomatoes and AABBCC produces 160 gm. Tomatoes;
each gene ( capital letter) causing an increase of 10 gm. Give the weight of tomatoes in the parents and
progenies in the following crosses. [a] AAbbcc X aaBBcc [b] AAbbcc X AaBbCc [c] AaBbCc X aaBbCc
[d] AaBbCc X aaBBCc [e] AaBbCc X AaBbCc [f] AABBcc X AaBBCc [g] aabbCc X AABbcc
Q.13. A tall yellow, round plant crossed with a dwarf, green, round one produced 91 tall, green,round
offsprings; 94 tall,yellow,round; 93 dwarf,green round and 90 dwarf, yellow round ones.determine the
genotype of parents?
Q. 14. A tall , green, round plant crossed with a dwarf,yellow,round one, produced 29 tall,green,round; 10
tall, yellow,round; 9 dwarf,green,round and 3 dwarf,yellow , round individuals in F-2. Determine the
genotype of P-1 parents?
Q.15. In pigeons, the checkered pattern is dependent on a dominant gene C and plain on recessive allele c.
Red colour is controlled by a dominant gene B and brown by the recessive allele b. Diagram completely
a cross between homozygous checkered red and plain birds. Summarised the expected F-2 results?
Q.16. In man the difference in skin colour between whites and Negroes is due to two pairs of factors. AABB
is black and aabb is white. Any three of the colour producing factors produce dark skin, any two
medium and any one is light.
[a] what will be skin colour of offsprings from a mating of white with black and form a mating of two F-1
individuals.
[b] Medium X light gives 2/16 dark; 6/16 medium; 6/16 light; 2/16 white. Give the genotype of
parents.
Q.17. Two pairs of polygenes AABB have cumulative effect and govern the seed weight in oats. A variety
with an average of 6 gm. Of oat per plant is crossed to another variety yielding an average 15 gm. Of
oat per plant. What will be the phenotype of F-1 anf F-2 ?
Q.18. A roan bull is bred to three cow. Cows a has the same genotype as the roan bull.Cow B is red and
Cow C is white.what proportions of roan cows are expected in the offspring of each group of cows?
Q.19. A green maize plant when selfed, produced about 15/16 green and 1/ 16 white(lethal) seedlings. Find
out the genotype of the plant and mode of inheritance of pigment.
Q.20. Suppose skin colour in man is influenced by two pairs A-a and B-b; so that AABB is black and aabb is
white and between these are dark, medium and light skin colours. A medium X light negro cross gives
1/8 dark, 3/8 medium; 3/8 light and 1/8 white. What are the genotype of parents?
Q.21. A woman bears a child with erythroblastosis foetalis at her second delivery. She has never a blood
transfusion. On the basis of this information, classify the woman, her husband and both children as to
Rh blood type?
Q.22. Two sets of parents Mr. X and Mrs. X; Mr. Y and Mrs. Y are claiming the same baby. Blood tests give
the information that Mr. X and Mrs. X belong to A group of blood; and Mr.Y belong to O group and
Mrs. Y is of AB group. The child belongs to O . Explain with reasons to which parents the child can be
given?
Q.23. In the following crosses you make total number of gametes; total no. of progenies; genotypic and
phenotypic ratio-? [a] RrYY X rrYy [b] AaBbCCddEe X aaBBCcDDEe [c] RrYYtt X RRttYy
[d] RrYyTtAa X rrYYTtAa [e] RRYYttAa X rrYyttAa [c] RrYytt X RrYyTt
Q.24. A couple prepairing for marriage have their blood typed along with other requirement blood tests.
Both are AB.They ask you what type of blood group their children may have.What would you tell them
and how would you explain your conclusions?
Q.25. Construct a map of chromosome, given the following map distances between individual pairs of
genes.:-- r----c = 10 units; c---P = 12 units; P—c= 3 units; s----c = 16 units ; s----r = 8 units.
Q.26. In a dsDNA there are 8000 nucleotides; If A= 18%; then you find out total number of G; total
number of hydrogen bonds and total length of this DNA?
Q.27. The test cross of an F-1 individual with genotype(++/ab) produced the followings:-- ++/ab---10 ;
ab/ab---10; +a/ab---40; +b/ab---40. Based on this data ; predict the configuration of F-1 heterozygotes?
Q.28. Individual homozygous for “cd “ genes were crossed with wild type(++).The F-1 dihybrids thus
produced was test crossed.It produce in the following ratio-- ++900; cd-880; +d-115; +c-105.what is the
distance between ‘c’ and ‘d’ genes?
Q.29. A woman with two genes,one for hemophilia and one for colourblindness on one of its
X-chromosomes; marries a normal man. The progeny will be------?