Mendel’s success was largely due to his choice of the garden pea plant for his experiments. The advantages of using this plant included:
I. Presence of easily observable contrasting traits for many characters.
II. It was possible to control pollination [and hence mating] between different pea plants.
III. A large number of seeds could be produced and statistical analysis was therefore more accurate.
IV. A long generation time means expression of all traits completely.
V. Many observable traits were controlled by single genes.
1. Only I, II and III
2. Only I, II and V
3. Only I, II, III and V
4. Only II, III, IV and V
What was the most significant conclusion that Gregor Mendel drew from his experiments with pea plants?
(1) There is considerable genetic variation in garden peas.
(2) Traits are inherited in discrete units, and are not the results of ʺblending.ʺ
(3) Genes are composed of DNA.
(4) An organism that is homozygous for many recessive traits is at a disadvantage.
Which of the following about the law of segregation is true?
(1) It states that each of two alleles for a given trait segregate into same gametes.
(2) It can be explained by the segregation of heterologous chromosomes during meiosis.
(3) It can account for the 3:1 ratio seen in the F2 generation of Mendelʹs crosses.
(4) It is a method that can be used to determine the number of chromosomes in a plant.
In guinea pigs, black coat color is a dominant trait and white is a recessive trait. When heterozygous black pigs are intercrossed the chance of the first two offspring being black is:
(1) 75 %
(2) 56 %
(3) 44 %
(4) 6 %
An organism with two copies of the same allele is:
(1) Homozygous for that trait
(2) Homologous for the allele
(3) Heterozygous for that trait
(4) Heterologous for the allele
Two heterozygous tall plants are intercrossed, what percentage of tall progeny will be homozygous tall?
(1) 25
(2) 33
(3) 50
(4) 66
Given the parents AABBCc × AabbCc, assume simple dominance and independent assortment. What proportion of the progeny will be expected to phenotypically resemble the first parent?
(1) 1/4
(2) 1/8
(3) 3/4
(4) 3/8
In a cross between AABB X aabb, the ratio of F2 genotypes between AABB, AaBB, Aabb and aabb would be:
(1) 9 : 3 : 3 : 1
(2) 2 : 1 : 1 : 2
(3) 1 : 2 : 2 : 1
(4) 7 : 5 : 3 : 1
The minimum progeny population size allowing for random union of all kinds of gametes from AaBbCc parents is:
(1) 9
(2) 16
(3) 27
(4) 64
In peas, a tall, yellow-seeded plant is crossed with a homozygous short, green-seeded plant. The numbers of progeny are: 203 [tall, green-seeded plants], 199 [short, green-seeded plants], 207 [tall, yellow-seeded plants] and 192 [short, yellow-seeded plants]. The most likely genotype of the tall, yellow-seeded parent is:
(1) TtYy
(2) TTYY
(3) ttYY
(4) ttyy
How many unique gametes could be produced through independent assortment by an individual with the genotype AaBbCCDdEE?
(1) 4
(2) 8
(3) 16
(4) 32
Two heterozygous round yellow seeded pea plants are intercrossed. In the progeny, the trait for seed shape will segregate in the ratio:
(1) 1 : 1
(2) 3 : 1
(3) 1 : 1 : 1 : 1
(4) 9 : 3 : 3 : 1
Which of the following terms best describes when the phenotype of the heterozygote differs from the phenotypes of both homozygotes?
(1) Incomplete dominance
(2) Multiple alleles
(3) Codominance
(4) Epistasis
A man of blood group A marries a woman of AB blood group. Which type of progeny would indicate that man is heterozygous A?
(1) AB
(2) A
(3) O
(4) B
You are studying the genetics of bean pigmentation in a particular variety of bean plant. A bean plant that produces grey beans is self-pollinated and the numbers of each progeny type produced are - 50 white beans 107 grey beans 38 black beans. Assuming that TWO genes govern the bean pigmentation trait, the genetic hypothesis that best explains the inheritance pattern of bean pigmentation would be:
(1) dominant/recessive
(2) incomplete dominance
(3) incomplete penetrance
(4) recessive epistasis
The gene for eye color in a certain organism has seven alleles. How many genotypic combinations are possible?
(1) 2
(2) 14
(3) 28
(4) 56
In chickens, gene R produces a rose-shaped comb, gene r produces a single comb, gene P produces pea-shaped comb and gene p produces a single comb. When P and R are both present in the genotype, the comb is walnut shaped. Two chickens with genotype RrPp are intercrossed. What will be the ratio of Walnut shaped, Rose shaped, Pea shaped and single comb progeny respectively:
(1) 3 : 1 : 1 : 3
(2) 1 : 1: 1 : 1
(3) 9 : 3 : 3 : 1
(4) 12 : 3 : 4
Two pure lines of corn have mean cob lengths of 9 and 3 inches respectively. The polygenes involved in this trait all exhibit additive gene action. Crossing these two lines is expected to produce a progeny with mean cob length [in inches] of:
(1) 12.0
(2) 7.5
(3) 6.0
(4) 2.75
Diseases that are caused by the malfunction of a pleiotropic gene are:
(1) cured by dietary restrictions
(2) reversible by gene therapy
(3) called as syndromes
(4) extremely rare
Out of a pair of monozygotic twins, one develops hare lip and the other does not. This can be an example of the genetic phenomenon of:
(1) Pleiotropy
(2) Incomplete penetrance
(3) Variable expressivity
(4) Incomplete dominance