Problem
A particular trait (height) in oil palm may be controlled by five QTLs (Quantitative Trait Loci) when analyzed in genetic background A, but seem to be influenced by eight QTLs in genetic background B, when analyzed within the same environment and age. Both these genetic backgrounds (A and B) are from the same species of oil palm, although they may have undergone different degrees of breeding. (i) Explain why one genetic background can have five QTLs while the other has eight QTLs for exactly the same trait. (ii) Is the first genetic background missing three genes?
In an oil plant, three recessive traits - virescence fruits are recessive to nigrescence fruits; purplecoloured anthiocynin-stained seedlings are recessive to green seedlings; and short plants recessive to normal plants. A true-breed normal plant with nigrescence fruits and green seedlings, was crossed to a short plant with virescence fruits and purple seedlings. The F1 plants were then crossed to a short plant with virescence fruits and purple seedlings, resulting in the following: 2111 nigrescence fruits, green seedlings, normal plants 287 nigrescence fruits, green seedlings, short plants 329 nigrescence fruits, purple seedlings, normal plants 23 nigrescence fruits, purple seedlings, short plants 1987 virescence fruits, purple seedlings, short plants 178 virescence fruits, purple seedlings, normal plants 285 virescence fruits, green seedlings, short plants 19 virescence fruits, green seedlings, normal plants Construct a genetic map that describe the map distance between these three genes.