A person who is trisomic for twenty first pair of chromosome suffers from

• Klinefelter's syndrome

• Down's syndrome

• Turner's syndrome

• None of the above

In which blood group antigen are absent

• O

• A

• B

• AB

123.

Which one of the following can help in the diagnosis of a genetical disorder?

• ELISA

• ABO blood group

• PCR

• NMR

The children of a haemophilic man and a normal woman are

• all haemophilic

• only daughters are haemophilic

• only sons are haemophilic

• neither sons nor daughters are haemophilic

If a plant having yellow or round seeds was crossed with another plant having green and wrinkled seeds then F, progeny are in the ratio

• 15 : 1

• 1 : 15

• 1 : 13

• all yellow and round seeds

A man of blood group 'A', marries a woman of blood group 'B', both of them are heterozygous for blood group, chances of their first child having blood group AB will be

• 25%

• 50%

• 75%

• 100%

2n-1 condition represent

• tetrasomy

• trisomy

• monosomy

• multisomy

2n - 1 condition is called

• trisomy

• monosomy

• nullisomy

• tetrasomy

When paternal and maternal chromosomes change their materials with each other in cell division this event is called

• synapsis

• crossing over

• bivalent forming

• dyad- forming

Which of the following conditions represents a case of codominant genes

• A gene expresses itself, suppressing the phenotypic effect of its alleles.

• Genes that are similar in phenotypic effect when present separately, but when together interact to produce a different trait.

• Alleles, both of which interact to produce a trait, which may or may not resemble either of the parental types.

• Alleles, each of which produces an independent effect in a heterozygous condition.