Mendel performed his experiments on pea plants,i.e pisum sativum.After eight years of tedious experiments with pea plants, he proposed three fundamental principles of inheritance.These principles eventually assisted clinicians in human disease research,e.g after a few years of the discovery of Mendel's work,Archibald Garrod applied Mendel's principles to his study of alkaptonuria.Today, Mendalwhether we talk about pea plants or humans,genetic traits that follow the rules of inheritanceMendel proposed are called Mendelian Principles.

Mendelian experiments cannot be carried out in human beings because:
(i) Generation period is long in human beings. Human traits are influenced by a number of factors.
(ii) Human inheritance cannot be studied in more than two to three generations by a scientist. Progeny of a couple is small.
(iii) Marriage desired by an experimenter are not always possible in humans.
(iv) They have a mixed population and pure traits are rarely observed.
(v) Marriages are not planned, so that there is regular mixing of traits coming from unconnected families.

In certain organisms, e.g.maize, Asparagus, Neurospora, yeast, etc., single gene pair is found to be responsible for determination of sex. e.g. Asparagus is a dioecious plant in which female flowers bear rudimentary anthers and male flowers bear rudimentary pistils, but it is seen that male flowers sometimes set the seed.
In one such case, when seeds obtained from a rare male flower, were raised into plants the male and female plants to be present in the ratio of 3:1 as:

In this case, maleness should be dominant over femaleness and the male plant is generally heterozygous. When male plants were used to pollinate female flowers only 2/3rd of them showed segregation, suggesting the control of sex by a single gene pair.
In maize, the gene for tassel seed (male inflorescence is called tassel) converts tassel into bearing inflorescence. Similarly, the gene for skillless (silk is female inflorescence) sk causes the absence of silk.
Therefore, the plants which
(i) sk/sk combination is a male plant.
(ii) ts/ts combination is a female plant.
By using the combination of these genes, it is possible to convert monoecious maize plant to a dioecious maize plant.

(i) Klinefelter's. It occurs due to trisomy of sex chromosome.
(ii) She was advised to undergo MTP since the child will have the following problems.
(a) male with feminine traits gynaecomastia
(b) underdeveloped testes leading to sterility
(iii) Yes, this test is actually to determine the genetic defects of metabolic disorders in foetus by doing a chromosomal analysis. In such extreme cases that could be incurable, a decision to abort the foetus could be taken. But, amniocentesis is misused now-a-days.
It is used to determine the sex of the foetus and in many cases it lead to female foeticide. It has become so serious that it disturbed the male-female ratio, that can have a negative impact on society. So, it should be banned.

Several group systems have been defined on the basis of antigens located on the surfaces of RBCs. Each of the blood group system is determined by a different gene or set of genes. Two blood group systems that have special medical significance are the ABO and Rh systems.
The mentioned condition is related to Rh blood group system. Rh factor is found only in man and rhesus monkey. Based on its presence or absence, human beings are as Rh⁺ or Rh^- , respectively.
It is through that Rh⁺ is a dominant character over a Rh^- which is recessive. Rh factor plays a crucial role in child's birth out of a marriage between Rh^- woman and a Rh⁺  man. In such a case, the mother becomes sensitive while carrying a first Rh⁺ child within her womb.
The reason for such sensitivity is that some of the RBCs from the developing embryo get into the bloodstream of the mother during development, causing her to produce anti-Rh antibodies. In fact, the first child of such parents is nearly normal and is delivered safely.
However, if such a mother gets pregnant again, the subsequent Rh⁺ foetuses will be exposed to the anti-Rh antibodies produced by the mother. As a result serious damage to the red blood cells of the developing embryo will occur causing Haemolytic Disease of the Newborn (HDN) or erythroblastosis foetilis.
This disease leads to the death of the developing embryo before birth or after parturition.

In a monohybrid test cross, involving a heterozygous tall plant (Tt) and a pure dwarf plant, the progeny consists of tall and dwarf plants in the ratio of 1:1

The type of inheritance is cytoplasmic or mitochondrial inheritance because the character in the given pedigree analysis is inherited only through female.

The phenomenon is point mutation that involves substitution of a single nitrogenous base in DNA.

(i)differences,offsprings
(ii)germ,somatic
(iii)charles Darwin,pangenes,
(iv)Hugo devries,Karl Correns,T-shermak
(v)Garden pea
(vi)3:1 ; 1: 2 : 1.

Sutton and Boveri noted that the behaviour of chromosomes was parallel to that of genes.
(i) Both genes and chromosomes occur in pairs.
(ii) They segregate during gamete formation and only one member of a pair enters one gamete.
(iii) One pair of genes 'or chromosomes segregates independently of the other pairs.
(iv) Since the number of chromosomes is far less than the number of genes or traits an organism possesses, it is proposed that a number of genes are located on every chromosome.