Klinefelter's syndrome - 44AA+XXY
Turner's syndrome - 44AA+XO

Mary Lyon suggested that Barr bodies represented an inactive chromosome, which in females becomes tightly coiled into a heterochromatin, a condensed and visible form of chromatin. The number of Barr bodies observed in cell was one less than the number of X-Chromosome. XO females have no Barr body, whereas XXY males have one Barr body.

It is the transmission of a gene from mother to son or father to daughter.
These patterns of inheritance are called criss-cross inheritance (or) skip generation inheritance in which a character is inherited to the second generation through the carrier of first-generation.
E.g., Wing color in the magpie moth (Abraxus) feather pattern in chickens

The methods adopted for the improvement of human beings are
(i) Eugenics
(ii) Euthenics
(iii) Euphenics
Eugenics:
Application of the laws of genetics for the improvement of human race is called eugenics. The term eugenics means "well born" and was coined by Francis Galton in 1885. For the betterment of future generations it is necessary to increase the population of outstanding people and to decrease the population of abnormal and defective people by applying the principles of eugenics.
Two methods of Eugenics
(i) Constructive method or Positive eugenics
(ii) Restrictive method or Negative eugenics
(i) Positive eugenics: Positive eugenics attempts to increase consistently better or desirable germplasm and to preserve the best germplasm of the society. The desirable traits can be increased by adopting the following measures:
a) Early marriage of those having desirable traits
b) Subsiding the fit and establishing sperm and egg banks of precious germplasm 
c) Educating the basic principles of genetics and eugenics
d) Improvement of environmental conditions
e) Promotion of genetic research
(ii) Negative eugenics: Negative Eugenics attempts to eliminate the defective germplasm of the society by adopting the following measures:
(a) Sexual separation of the defectives
(b) Sterilization of the defectives
(c) Control of immigration and
(d) Regulation of marriages
Euphenics:
man is called Euphenics or Medical engineering. In 1960, Joshua Lederberg coined the term Euphenics. It means normal appearing. It deals with the control of several inherited human diseases especially the inborn errors of metabolism. Eg. Phenylketonuria (PKU)
Euthenics:
The science of improvement of existing human race by improving the environmental conditions is called euthenics. It can be achieved by subjecting them to better nutrition, better unpolluted ecological conditions, better education and sufficient medical facilities

(i) Certain characters are controlled by nonnuclear genomes found in chloroplast, mitochondria, infective agents and plasmids. These characters do not reveal Mendelian pattern of inheritance.
(ii) The inheritance of the extra chromosomal genes are found to exhibit maternal influence.
(iii) Although both male and female parents contribute equally to the zygote in terms of chromosomal genes, the female parent usually contributes the zygote's initial cytoplasm and organelles, since the sperms contain very little cytoplasm. If there are hereditary units in the cytoplasm, these will be transmitted to the offsprings through the egg, so the offsprings exhibit maternal effect.
(iv) The cytoplasmic extranuclear genes have a characteristic pattern of inheritance which do not resemble the genes of nuclear chromosomes and is known as extra chromosomal or extra nuclear or cytoplasmic inheritance and exhibit maternal influence.
(v) In extra nuclear inheritance, male and female parents contribute equally their nuclear genes to the progeny but do not make equal contribution of' extra chromosomal genes hence, the crosses can yield different (or) non Mendelian results. Extra chromosomal inheritance in Limnaea peregra.
(vi) Limnaea peregra is a freshwater snail. The shell of these animals are spirally coiled. The coiling of the shell is clockwise (dextral) or anticlockwise (sinistral).
(vii) Both type of coilings are produced by two. different types of genetically controlled cleavages namely, dextral cleavage and sinistral cleavage.
(viii) In Limnaea, dextral coiling is normal and Sinistral coiling is a mutant character.
(ix) Direction of coiling is determined by a pair of nuclear genes, D( dextral) and d (sinistral). The gene for dextral (D) being dominant over sinistral coiling (d). In Fig. a dextral snail provides the eggs and a sinistral snail provides the sperm. The offsprings are all dextral (Dd), in the F1 generation.
(x) When the F1 heterozygous dextral individual (Dd) were self crossed the F2 generation showed dextral coiling with genotype of IDD, 2Dd and l dd.
(xi) When a reciprocal cross is made the F1 individuals have Dd genotype but are coiled sinistrally, as in the female parent. In both the crosses the Flare phenotypically similar to the female parent, though the offsprings in both crosses have the same genotype Dd. This is because the genotype of the maternal parent determines the phenotype of the offspring.
(xii) When the F1 sinistral individuals were self crossed, the shell coiling in the F2 generation, were all dextral. This is because the genes do not segregate in the F2 generation. Only in the F3 generation segregation occurs in the ratio of 3 dextral: 1 sinistral.
(xiii) Reasons: The type of cleavage depends on the organization of the egg which is established before the maturation division of the oocyte nucleus and by the influence of the maternal genotype.
(xiv) The direction of coiling of the shell depends upon the orientation of the mitotic spindle during the first cleavage.
(xv) Obviously, maternal control affects only one generation. In each generation the coiling is dependent on the maternal genotype.

Genetic basis of blood grouping in human population
1. ABO blood grouping in human shows the phenomenon of codominance.
2. Alleles are able to express themselves independently when present together.
3. More than two alleles govern the same character.
4. Karl Landsteiner discovered two kinds of antigens called antigen 'A' and antigen 'B' on the surface of RBC's of human blood.
5. In 1902 two of Landsteiner's students Von De Castelle and Sturli discovered fourth rarest blood group 'AB' (universal recipient).
6. Bernstein in 1925 discovered that the inheritance of different blood groups in human beings is determined by a number of multiple allelle series.
7. The three autosomal alleles located on chromosome are concerned with the determination of blood group in any Person.
8. The gene controlling blood types has been labeled as 'L' (after the name of the discoverer, Landsteiner) or I (from iso -agglutination).
9. The I gene exists in three allelic forms, I^A, I^B and I^o specifies A antigen.
10. I^B allele determines B antigen and I^o allele specifies no antigen.
11. Individuals who possess these antigens in their fluids such as the saliva are called secretors
Genetic basis of the human ABO blood groups
Genotype ABO blood group phenotype Antigens present on red blood cell Antibodies present in blood plasma I^AI^A Type A A Anti -B I^AI^O Type A A Anti -B I^BI^B Type B B  Anti -A I^BI^O Type B B Anti -B I^AI^B Type AB A and B Neither Anti - A nor Anti -B I^OI^O Type O Neither A nor B Anti - A and anti -B

Preparation of Karyotype Tjio and Levan (1960) described a simple method of culturing lymphocytes from the human blood. Mitosis is induced followed by addition of colchicine to arrest cell division at metaphase stage and the suitable spread of metaphase chromosomes is photographed. The individual chromosomes are cut from the photograph and are arranged in an orderly fashion in homologous pairs. This arrangement is called a karyotype. Chromosome banding permits structural definitions and differentiation of chromosomes.

(i) If the mother is Rh negative and foetus is Rh positive, anti D antibodies should be administered to the mother at 28th and 34th week of gestation as a prophylactic measure.
(ii) If the Rh negative mother delivers Rh positive child then anti D antibodies should be administered to the mother soon after delivery.
(iii) This develops passive immunity and prevents the formation of anti D antibodies in the mothers blood by destroying the Rh foetal RBC before the mother's immune system is sensitized.
(iv) This has to be done whenever the woman attains pregnancy.

D. Both A and R are false.

(c) ii only

(a) Barr body
Reason: It deals with dosage compensation in sex determination whereas others linked to haplodiploidy

Joshua Lederberg

Huntington's choreal

thromboplastin