Question

1. Briefly mention the contribution of T.H. Morgan ln genetic?
2:What is pedigree analysis? Suggest how such an analysis, can be use
3. How is sex determined in human beings?​

Answer 1

The discoveries made by T. H. Morgan forms the basis of modern Genetics.

Explanation:

1) T.H. Morgan, made many contributions in the field of genetics, out of which his main contribution is:

• The formulation of Chromosomal Theory of Linkage, in which he defined the linkage between the genes and how it affects the expression of characters in the future progeny.
• His experimental material for these experiments were Fruit fly, or Drosophilla melanogester.
• For his contribution to the field of medicine especially genetics he was awarded Nobel Prize in Physiology and Medicine in 1933.

2) Pedigree analysis is a type of chart in which various genetic informations are shown by the means of family tree.

• Since the life span of human beings are long, and it is not possible to perform cross between humans for ethical reasons, geneticists had to resort to family tree in which various sex linked characters.
• Pedigree analysis can be used to analyze various dominant and recessive traits distributed in the family. For example, the trait of Hemophilia, Colour blindness, etc can be analysed using Pedigree analysis.

3) The Y chromosome in Human beings determine the sex of the child.

• Human beings have 23 pair of chromosomes, out of which 22 are autosomes which controls the autosomal or body characters.
• One pair consisted of sex chromosome which determines the sex of the baby.
• Females have one pair of X chromosome and their genetic makeup is 22 + XX.
• While males also have one pair of sex chromosome but their genetic makeup is 22 + XY.
• This Y chromosome decides the sex of the body, therefore the sex of the body is determined by his/ her/ their father and not their mother.

Answer 2

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▶ pedigree analysis is the study of transmission of particular traits over the generations for finding out the possibility of their occurrence in the future generation...

▶importance

☀ it is used to know the possibility of expressive or recessive allele which may cause genetic disorder

☀ it shows the origin of trait and inheritance pattern of that trait in a family

☀ it predict the harmful effect of marriage between close relatives

☀ it extenously used in medical research ..