A lower proportion of copia, mdg1 and 412 element insertion sites on the X chromosome, from various populations of D.melanogaster and D.simulans, in comparison with autosomes suggests that selection against the detrimental effects of TE insertions in the major force containing TE copies in populations.
Dsim\mdg1 elements are enriched in the heterochromatin and on the Y chromosome.
A lower proportion of copia, mdg1 and 412 element insertion sites on the X chromosome, from various populations of D.melanogaster and D.simulans, in comparison with autosomes suggests that selection against the detrimental effects of TE insertions in the major force containing TE copies in populations.
Numbers of mdg1, mdg3, gypsy and copia have been studied in several strains of D.melanogaster and D.simulans. Mean number of mdg1 and copia sites are drastically reduced in D.simulans. Majority of mdg1 and copia sites, and one third of mdg3 sites, are in hot spots for insertion, particularly in D.simulans. Southern blot analysis indicates that the majority of mdg1 and copia are in the euchromatin of D.melanogaster but the heterochromatin of D.simulans.