Fill in the blanks and choose the correct option given below.

(i) Sickle-cell anaemia is caused by the substitution of by at 6 th position of the globin chain of Haemoglobin.

(ii) In phenylketonuria, the individual lacks an enzyme that converts the amino acid phenylalanine into .

(iii) Failure of segregation of chromatids during cell division cycle results in the grain or loss of a chromosome called .

(iv) In , there is an increase in a whole set of chromosome in an organism.

(v) Down ’ s syndrome is genetic disorder because of presence of an additional copy of chromosome number .

(vi) In syndrome, there is an additional copy of X-chromosome resulting into a karyotype of 47, XXY.

(vii) In syndrome, there is an absence of one of the X-chromosome, i.e. 45 with XO.

(viii) The traits that are generally controlled by 3 or more genes are called traits.

(ix) When single gene exhibit multiple phenotypic expression, it is called gene.

(x) In honey bee, females are having chromsome and males are having 16 chromosome. This is called sex-determination system.

(xi) Colour blindness is -linked disorder. This defect is due to mutation in certain genes present in chromosome.

(xii) Thalassemia is -linked genes and on chromosome of each parent.