Cucurbitaceae are a plant family consisting of about 965 species. Well known genera are Cucurbita (squash, pumpkin, zucchini, some gourds), Lagenaria (calabash), Citrullus (watermelon), Cucumis (cucumber, various melons) and Luffa (luffa). This great diversity is related species wouldn't have been possible if it weren’t for an ancient event in plant evolution.
The researchers compared the genomes and evolutionary trees of a number of plants including cucumbers, melons and gourds. Millions of years of environmental changes allowed the fruits to lose genes over time and tailor their own codes to become what we know them as today.
After each major divergent event, genes were deleted, chromosomes were rearranged and new genetic patterns were created. Knowing more about which genes survived to do different things in each plant means scientists can now get closer to creating even more variations of these fruits.
 Wang et al: An overlooked paleo-tetraploidization in Cucurbitaceae in Molecular Biology and Evolution - 2017