Table 4.

Relative repeat gain of current sex chromosomes compared with putative ancestral autosome(s). Size and composition of putative ancestral autosome(s) were calculated assuming (1) the composition of the ancestral autosome was similar to that of the current autosome library, and (2) the absolute amount of the non-repetitive portion of the sex chromosomes did not change drastically during their evolution. Indicated errors account for differences when Y chromosomes and X non-repetitive portion were used for calculation of ancestral autosome(s) size

Repeat type		X relative gain (%)	Y relative gain (%)
LTR retrotransposon	Ty1/Copia	+55 ± 5	+92 ± 6
	Ty3/Gypsy	+121 ± 7	+186 ± 10
Non-LTR	LINE	−15 ± 3	+23 ± 4
DNA transposon		−37 ± 2	−11 ± 3
Satellites		+30 ± 4	+561 ± 22
Not annotated		+36 ± 5	−47 ± 2