Who are the ancestors of the modern day greek islanders ?

in general ..or ıs there any genetıc studıes ?..would they stıll be descended form pelasgians etc or ıonıans or even dorıans and are they sımılar gentıcally to the maınland greeks or more to anatolia(turkey)..(ı hear that the modern day turkısh populatıon ın the majorıty derıves from varıous dıfferet ancıent anatolıans) .. as a sıdenote my grandmother comes from andros island