Inheritence

Question 1

In the result of self-fertilization of dihybride cross the ratio of seeds which contain both dominant characters is

Answer 1

9/16
RrYy × RrYy
=> Cross them by using punet’s square
Then:
=> Phenotype: 9 : 3 : 3 : 1
9 = Round Yellow
3 = Round green
3 = Wrinkle yellow
1 = Wrinkle green

Question 2

The distance between gene A and B is 9 centiMorgan and B and C is 9.5 the actual distance between A and C will be

Answer 2

9+9.5 = 18.5% = actual distance
=> 17% Recombinant frequency

Question 3

The property due to which offspring show similarities with their parents is called

Answer 3

heredity
=> Characters transfer from parent called inheritance.
=> If phenotype of parental same as in offspring, then it is called hereditary.
genetics is variation and heredity

Question 4

If phenotype is O because of recessive H gene the possible I gene may be

Answer 4

any of them
Hh, HH => h substance present so antigen present
hh => h substance absent so antigen is absent
=> If H substance is missing it masks the effect of the (I gene) and genotype will be A, B, AB but phenotype will be O Blood group.

Question 5

Blood group O is universal donor because of

Answer 5

antigen
=> Donor depends on Antigen
=> Recipient depends on antibody
↳ Both for blood transfuse
no antigen ← O -ive = universal donor
AB +ive = universal acceptor

Question 6

During determination of gene linkage the ratio of recombinant is similar to parental , the genes are

Answer 6

{Parental = Recombinant} → No linkage
{All parental} → complete linkage
{More parental, Less recombinant} → incomplete linkage

Question 7

Interaction between alleles of different genes is called

Answer 7

non allelic and epistasis
both are intergenic interactions

Epistasis occurs when two or more different gene loci contribute to the same phenotype, but not additively. Epistasis is often described as occurring when one gene locus masks or modifies the phenotype of a second gene locus. The epistatic gene pair is present on non-homologous chromosomes, an interaction that is termed as non-allelic.

Question 8

XXY in drosophila represent

Answer 8

fertile female
Male ← XXY = Kline filter syndrome in human
Female ← XXY = in drosophila fertile
Female

Question 9

In a dominant relation the interaction is

Answer 9

inter allelic
=> According to Mendelian inheritance there is inter allelic interaction
=> Non Mandelian inheritance have intergenic interaction (interaction b/w alleles of different genes)

Question 10

The genotypic ratio of F2 generation in monohybrid cross is

Answer 10

1:2:1
Genotype in F2:
RR Rr rr
1 : 2 : 1
Phenotype in F2
3 : 1

Question 11

Number of linkage groups in drosophila are

Answer 11

4
No of linkage groups in an organism are equal to number of homologous pair of chromosomes.
⟹ Drosophila has 4 homologous pair of chromosomes so 4 linkage groups.
Linkage groups
Linkage group refers to a group of genes which are present in one chromosome. In other words, all those genes which are located in one.
Chromosome constitute one linkage group. The number of linkage groups is limited in each individual. The maximum number of linkage groups is equal to the haploid chromosome number of an organism.
For example: There are ten linkage groups in corn (2n = 20), seven in garden pea (2n = 14), seven in barley (2n = 14), four in Drosophila melanogaster (2n = 8) and 23 in man (2n = 46).

Question 12

what were the characteristics studied by mendel
in a pea plant

Answer 12

Following seven characteristics were studied by Mendel:
1) Flower color 2) Flower position
3) Seed shape 4) Seed color
5) Pod shape 6) Pod color
7) Stem height
conducted exp on 29,000 pea plants

Question 13

The contrasting pair of a factor in Mendelian crosses are called:

Answer 13

alleles
The contrasting pairs of factors in Mendelian crosses are called allelomorphs or Alleles.

Question 14

Y-linked, or holandric genes include the gene that initiates

Answer 14

differentiation of the embryo into a male, several genes that encode testis specific spermatogenesis factors, a minor histocompatibility antigen (termed HY), and a gene in which mutations can cause hearing loss (DFNY1).
♦ Y-linked or holandric inheritance implies that only males are affected.
♦ Male-to-male transmission. An affected male transmits Y-linked traits to all of his sons but to none of his daughters.

Question 15

According to modern concept, Mendel’s factor is called as ________.

Answer 15

genes

Question 16

Mendel’s law of segregation is also known as _________________

Answer 16

Law of purity of gametes
When a pair of alleles is brought together in a hybrid (F1) they remain together without contaminating each other and they separate or segregate from each other into a gamete during the formation of gametes

Question 17

Which law states that the inheritance of one trait is independent on the inheritance of another trait?

Answer 17

Law of independent assortment
the allele a gamete receives for one gene does not influence the allele received for another gene.
According to the law of dominance, a trait is represented by two contrasting factors of a gene in a heterozygous individual; the allele/factor that can express itself in a heterozygous individual is called as a dominant trait. Whereas the law of segregation states that the two factors for a trait, present together in a heterozygous individual, do not get mixed and are separated during gametogenesis.
ratio is 9:3:3:1
◉ Using a dihybrid cross, Mendel developed the law of independent assortment.
◉ The law of independent assortment states that each pair of alleles segregates independently of each other pair of alleles during gamete formation.
◉ Strictly speaking, this law applies only to genes on different, nonhomologous chromosomes.
◉ Genes located near each other on the same chromosome tend to be inherited together.

Question 18

Which of the following crosses and ratio best demonstrates the law of segregation?

Answer 18

Aa×Aa
3:1
applies to non homologus chromosomes

Question 19

The Mendelian principle which has always stood true is

Answer 19

The law of segregation
n these principles, the law of dominance and Law of Independent assortment have deviations or exceptions. Law of segregation does not have any deviations of exceptions. So it always stands true.
Law of segregation is the universally accepted law of inheritance. It is the only law without any exceptions. It states that each trait consists of two alleles which segregate during the formation of gametes and one allele from each parent combines during fertilization, both parents contribute to the factors of offspring equally. In case, alleles of a pair are heterozygous, one is dominant and other recessive, alleles are not mixed up, the dominant one gets expressed. The recessive traits tend to reappear in the subsequent generation.
There is no such contrary model indicating that alleles mix up in the progeny so far, hence it is accepted and applicable

Question 20

Occasionally, a single gene may express more than one trait or effect. The phenomenon is called

Answer 20

This phenomenon is called pleiotropy, Polygeny refers to a single characteristic that is controlled by more than two genes

Question 21

ABO blood grouping in human is an example of

Answer 21

co dominance and multiple allelism

Question 22

Mendelian recombination’s are due to

Answer 22

Independent assortment of characters

Question 23

All genes located on the same chromosome

Answer 23

Form one linkage group

Question 24

Mendel’s perform series of experiments on pea plant because it’s _________?

Answer 24

Flowers were hermaphrodite
Had sharply distinct trait
Self-fertilization is easy

Question 25

sex determination for bees

Answer 25

N - male
NN - female
both are homogametic

Question 26

sex determination for chicken

Answer 26

ZZ - male
ZO- female

Question 27

Mendel used________________ for his experiment

Answer 27

Pisum sativum
garden pea

Question 28

describe heamophilla C

Answer 28

less than 1 percent
autosomal linakge on chromosome 19
equal chances in both sex

Question 29

Mendel was not imagining about which of the following?

Answer 29

Linkage
inkage of genes phenomenon was discovered by Bateson and Punnet (1906) in Lathyrus odoratus.

Question 30

Phenotype of an organism is the result of

Answer 30

Genotype and environment interactions

Question 31

what is the limit of crossing over frequency

Answer 31

it can’t exceed 50 perecnt

wow

Question 32

The mechanism that causes a gene to move from one linkage group to another is called

Answer 32

Translocation

Human have 22 autosomal linkage groups, one X and one Y linkage group. Rearrangement of chromosomal segment between two non-homologous chromosomes i.e., translocation moves gene of one linkage group to that of other, which occurs due to an induced abnormality and is not part of the regular cell cycle.
Inversion and duplication cause rearrangement of genes on same chromosome. There is a change in the order of genes within the same linkage group.
Crossing over results in exchange of genes between two homologous chromosomes. A process that occurs during Meiosis I resulting in recombination.

Question 33

Which one of the following trait undergo a zigzag pattern from maternal Grand-father to a Grand-son?

Answer 33

X-linked.
X-linked recessive trait follow a zigzag pattern. Son inherits X chromosome only from his mother and daughter gets X chromosome from each parent. So the X linked trait passes on from maternal grandparent to grand son through the daughter.

Question 34

In Drosophila sex is determined by

Answer 34

Ratio of number of X-chromosomes to the sets of autosomes

♦ Sex in Drosophila is determined by Genic Balance Mechanism.
♦ Ratio of X chromosomes: haploid sets of autosomes (X: A)
♦ X chromosome = Female producing effects
♦ Autosomes = Male producing effects
♦ Y Chromosome = Fertility factor in male
♦ X:A ratio
Female = 1.0 (2X:2n)
Male = 0.5 (1X:2n)
0.6 < X:A < 1.0 = intersex

Question 35

During his experiment, Mendel called the genes by the term

Answer 35

Elementen

Question 36

Hemophilia B is due to absence or abnormality of blood clotting factor:

Answer 36

IX

is 20%
A is caused by blood failing to clot agter injury