 The period that followed was marked by a strong increase in cranial capacity, promoting speculation that the loss of the gene may have removed an evolutionary constraint on brain size in the genus "Homo".Another estimate for the loss of the MYH16 gene is 5.3 million years ago, long before "Homo" appeared.Segmental duplications (SDs or LCRs) have had roles in creating new primate genes and shaping human genetic variation.