Down's syndrome is due to
crossing over
linkage
sex-linked inheritance
non-disjunction of chromosomes
A colourblind girl is rare because she will be born only when
her mother and maternal grandfather were colourblind
her father and maternal grandfather were colourblind
her mother is colourblind and father has normal vision
parents have normal vision but grand parents were colourblind
The hybrid test cross ratio will be:
9:3:3:1
1:1
1:1:1:1
2:1:1
Two similar chromosomes are called:
Homologous chromosomes
Locus
Allele
Genes
Diploid chromosome number in humans is
46
44
48
42
A dihybrid condition is
tt Rr
Tt rr
tt rr
Tt Rr
Genetic code consists of
adenine and guanine
cytosine and uracil
cytosine and guanine
All of the above
Sex is determined in human beings
by ovum
at the time of fertilization
40 days after fertilization
seventh to eight week when genitals differentiate in foetus.
Out of 8 ascospores formed in Neurospora the arrangement is 2a : 4a : 2a showing
no crossing over
some meiosis
second generation division
first generation division
Write the ratio of a typical of dihybrid cross.
2:4:4:1
2:1:1:0
9:1:16:1
