The distance between two genes in a chromosome is measured in cross-over units which represent
(1) ratio of crossing over between them
(2) percentage of crossing over between them
(3) number of crossing over between them
(4) none of these
How many genome types are present in a typical green plants cell?
(1) More than Five
(2) More than Ten
Percentage of recombination between A and B is 9%, A and C is 17%, B and C is 26%, then the arrangement of genes is
Which of the following conditions represents a case of co-dominance genes?
(1) A gene expresses itself, suppressing the phenotypic effect of its alleles.
(2) Genes that are similar in phenotypic effect when present separately, but when together interact to produce a different trait.
(3) Alleles, both of which interact to produce a trait, which may or may not resemble either of the parental types.
(4) Alleles, each of which produces an independent effect in a heterozygous condition.
Which of the following disorders are caused due to recessive autosomal mutations?
(1) Turner's syndrome and sickle cell anaemia
(2) Edward's syndrome and Down's syndrome
(3) Cystic fibrosis and phenylketonuria
(4) Alzheimer's disease and Huntington's chorea
Which of the following is correct ?
(1) Henking discovered the small Y-chromosome.
(2) Drosophila also shows XX-XY sex determination like human.
(3) Birds have ZZ-ZW sex determination, where females are ZZ and males are ZW.
(4) Grasshoppers show XX-XY sex determination.
Which of the following is true for a recessive disease in family A and B?
(1) In family A, both the parents are homozygous recessive.
(2) In family B, both the parents are homozygous dominant.
(3) In family B, both the parents are heterozygous recessive.
(4) In family A, both the parents are heterozygous recessive.
Which of the following occurs due to monosomy of sex chromosome?
(1) Down's syndrome
(2) Turner's syndrome
(4) Sickle cell anaemia
In rabbits, the gene for grey fur (G) is dominant over that for black fur (g). In a litter, if 50% rabbits are grey, then the possible parental cross combination is
(1) GG X Gg
(2) GG X GG
(3) gg X gg
(4) Gg X gg.
Barr body is missing in the female suffering from
(1) Huntington's disease
(2) Tay-sach's disease
(3) Klinefelter's syndrome
(4) Turner's syndrome