question_answer 29)

  The inheritance pattern of a gene over generations among humans isstudied by the pedigree analysis. Character studied in the pedigree analysis is equivalent to (a) quantitative trait       (b) Mendelian trait          (c) polygenic trait             (d) maternal trait

Answer:

                    (b) Mendelian inheritance in humans is difficult to study. Current understanding of mendelian inheritance in humans is gained by analysis of family pedigrees or the results of matings that have already occured. By analyzing a pedigree, we may be able to predict how the trait is inherited. It is a visual tool for documenting the biological relationship in families and to determine the mode of inheritance (dominant, recessive etc.,) of genetic diseases. Whereas quantitative trait, polygenic trait and maternal traits are not studied bypedigree analysis. Continuous traits are often measured and given a quantitative value, they are often referred as quantitative traits, e.g., crop yield, weight, gain in animals, IQ, etc. Polygenic traits are another exception to mendels rule, which occurs when a trait is controlled by more than one gene. This means that each dominant allele adds to the expression of the next dominant allele. Maternal traits are the traits inherited and expressed from the maternal parent to the subsequent offsprings.