It's not just genetics it's proximity to the equator.
For Filipinos, it's also due impregnation by southern Han BVLLs since Luzon is closer to China than it is to Mindanao.
Negritos don't even have the same genetics as each other in spite of the similarities in skin colour. >Indeed, this sentiment is echoed in a more recent work from 2013 which concludes that "at the current level of genetic resolution ... there is no evidence of a single ancestral population for the different groups traditionally defined as 'negritos'."[9] digitalcommons.wayne.edu/cgi/viewcontent.cgi?article=2055&context=humbiol