Data from: Nuclear markers reveal a complex introgression pattern among marine turtle species on the Brazilian coast

A surprisingly high frequency of interspecific sea turtle hybrids have
been previously recorded in a nesting site along a short stretch of the
Brazilian coast. Mitochondrial DNA data indicated that as much as 43% of
the females identified as E. imbricata are hybrids in this area (Bahia
State of Brazil). It is a remarkable find, since most of the nesting sites
surveyed worldwide, including some in northern Brazil, presents no
hybrids, and rare Caribbean sites present no more than 2% of hybrids.
Thus, a detailed understanding of the hybridization process is needed to
evaluate natural or anthropogenic causes of this regional phenomenon in
Brazil, which could be an important factor affecting the conservation of
this population. We analyzed a set of 12 nuclear markers to investigate
the pattern of hybridization involving three species of sea turtles:
hawksbill (Eretmochelys imbricata), loggerhead (Caretta caretta), and
olive ridley (Lepidochelys olivacea). Our data indicate that most of the
individuals in the crossings L. olivacea × E. imbricata and L. olivacea ×
C. caretta are F1 hybrids, whereas C. caretta × E. imbricata crossings
present F1 and backcrosses with both parental species. In addition, the C.
caretta × E. imbricata hybridization seems to be gender and species
biased, and we also found one individual with evidence of multispecies
hybridization among C. caretta × E. imbricata × Chelonia mydas. The
overall results also indicate that hybridization in this area is a recent
phenomenon, spanning at least two generations or ~40 years.