Fertilization - Part I
Three types of seed are obtained when an A-B translocation stock is
used as the male parent and the female parent is a normal, non-tranlocation
stock.
In this example the sugary gene (su) is located on the reciprocal translocation
A-B portion of the chromosome to serve as a genetic marker. The female
parent is su/su homozygous recessive. The male parent carries the dominant
allele (Su) at this locus on the translocated portion of the chromosome.
The male pollen can be of two types. Euploid male pollen is:
This euploid male pollen does not contain a duplicate or a deficiency
for the chromosome 4 because the entire chromosome is present. A portion
of the A-type of chromosome 4 is located on the B4 chromosome and the
remaining portion is located on the 4B chromosome. The other type of
male pollen is aneuploid. The aneuploid pollen has two sperm nuclei
which are not the same. One sperm nuclei is:
and this sperm nuclei has a duplicate segment for the portion of chromosome
4, which carries the Su locus.
The sperm nuclei is deficient for the portion of the chromosome 4 arm
which contains the Su locus. This sperm nuclei is:
4B
This anueploid type of pollen has the form:
