Lampbrush chromosomes in egg cells of vertebrates present many loops for mRNA synthesis.
lampbrush chromosomes were first seen by Flemmingin 1882 and named by Ruckert in 1892
well! Due to evolution..this type of giant chromosome came into picture...due to environmental changes and to adapt itself better with enviroment ..such change has been occured..such as high secreation in case of drosophila melanogaster...