Short Answer TypeUsing a Punnett Square, work out the distribution of phenotypic features in the first filial generation after a cross between a homozygous female and a heterozygous male for a single locus.
Long Answer TypeShort Answer TypeLong Answer TypeDefine and design a test cross.
â–² Fig. 1.3. Genetics of a test cross.
show the dominant character and 50% show the recessive character, i.e. F1 ratio is 1 : 1, the individual under test is heterozygous (Fig. 1.1). This is so because the individual showing the recessive trait (say white coat colour in guinea pig, dwarf size in pea plant) must have received one recessive allele (b in guinea pig, t in pea plant) from each parent.
If all the offspring of the test cross show the dominant trait, the individual being tested in homozygous dominant with genotype BB for guinea pig and TT for pea plant (Fig. 5.3).
When a cross is made between tall plant with yellow seeds (TtYy) and tall plant with green seeds (Ttyy), what proportions of phenotype in the offspring could be expected to be
(a) tall and green
(b) dwarf and green ?
Short Answer Type
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