An abnormal human baby with 'XXX' sex chromosomes was born due to
a.Fusion of two ova and one sperm
b.Fusion of two sperms and one ovum
c.Formation of abnormal sperms in the father
d.Formation of abnormal ova in the mother
Triple X syndrome occurs in women, who inherit three X chromosomes--their genotype is XXX. This type of syndrome is very rare and occurs due to defects in meiosis 1 and 2 during gamete formation in the mother and produces abnormal ova. Therefore, the correct answer is option D.
Sertoli cells are present in the seminiferous tubules of the male gonads, the testes. They were first observed in 1865 by a young Italian physician Enrico Sertoli and named after him. Sertoli cells comprise one of the two types of cells in the germinal epithelium, the other being of spermatogonia
Which one of the following organism's plasmid was used successfully for the first time as a vector by Stanley Cohen and Herbert Boyer?
a.Salmonella typhimurium
b.Streptococcus pneumoniae
c.Staphylococcus aureus
d.Rhizobium leguminosarum