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 . 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: (i) Early marriage of those having desirable traits (ii) Subsiding the fit and establishing sperm and egg banks of precious germplasm (iii) Educating the basic principles of genetics and eugenics (iv) Improvement of environmental conditions (v) Promotion of genetic research (ii) Negative eugenics Negative Eugenics attempts to eliminate the defective germplasm of the society by adopting the following measures: (i) Sexual separation of the defectives (ii) Sterilization of the defectives (iii) Control of immigration and (iv) Regulation of marriages XII Std Zoology Chapter XII Std Zoology Chapter Principles of Inheritance and Variation is called sex linked inheritance. Haemophilia, colourblindness, muscular dystrophy are some examples for X linked inheritance in human beings. Pedigree analysis is the study of traits as they have appeared in a given family line for several generations. The genetic disorders are of two types- Mendelian and chromosomal.
Alternations or mutation in single gene causes Mendelian disorders like, thalassemia, albinism, phenylketonuria, and Huntington’s chorea. Chromosomal abnormalities arise due to chromosomal non-disjunction, translocation, deletion, duplication and inversion. Downs syndrome, Klinefelter’s syndrome, Turner’s syndrome and Patau’s syndrome are some of the chromosomal disorders. Downs syndrome is due to trisomy of chromosome .
Presence of trisomic condition of chromosome results in Patau’s syndrome. In Turner’s syndrome the sex chromosome is XO and in Klinefelter’s syndrome the condition is XXY. An idiogram refers to a diagrammatic representation of chromosomes. The cytoplasmic extra nuclear genes have a characteristic pattern of inheritance which does not resemble genes of nuclear chromosomes and are known as Extrachromosomal/ Cytoplasmic inheritance.
The betterment of human race can be achieved by methods like Eugenics, Euthenics and Euphenics.