Free Will, or Destiny?

In the middle of the 19th century, Gregor Mendel’s experiments on pea plants revealed the secrets of heredity.  In the early 20th century, Thomas Morgan and his students, experimenting with fruit flies, found that genes on chromosomes were the causes of heritable traits.  Through much of the rest of the 20th century, Barbara McClintock’s experiments with maize (corn) demonstrated astonishing control genes that jumped about among chromosomes.
    Did these investigators choose their organisms?  Or did the organisms choose the investigators?  
    Mendel wanted to perform rigorously controlled crosses between specific plants.  He wanted to cross purple-flowered plants and white-flowered plants, smooth-seeded plants and wrinkly-seeded plants, tall and short, etc.  So he couldn’t allow chance pollinations to interfere.  The pea flower is perfect for this.  Pea flower petals stay closed during pollination.  The male anthers develop just above the female pistils, and the flower self-fertilizes before opening.  Mendel could open each flower before fertilization, snip out the anthers, and keep them in labeled packets while their pollen ripened.  Then he could brush his choice of pollen onto his choice of pistils to perform the crosses he wanted.  Yet Mendel couldn’t have known in advance that the traits he chose would all be separately heritable.  He couldn’t have known each would show both a dominant and a recessive version, allowing Mendel to use mathematical ratios to uncover heredity’s secrets.
    Thomas Morgan’s original plan was to experiment on mutations.  Fruit flies were ideal for this because they could be attracted into the lab with ripe bananas, because they were small enough to keep and breed in tiny, labeled bottles, and because their life cycle took only ten days, allowing series of experiments to take place over convenient periods.  But Morgan and his students discovered fruit flies had much more to offer.  Multiple mutations appeared, some connected with the sex of the insect, and odd chromosome aberrations made it possible to determine the exact location of any on each of the four fruit fly chromosomes.
    Barbara McClintock spent a lifetime working in maize genetics.  On each maize plant, the male flowers are the tassels at the top of a stalk, and the female flowers are the silks protruding from the corn ear.  Once pollinated, each silk results in a single corn kernel growing from the cob.  In her fields of corn, McClintock could simply cover the tassels and ears of each stalk with paper bags to prevent chance pollination.  Then, like Mendel, she could cross-pollinate or self-pollinate at will.  But corn offered so much more:  Each kernel showed the results of a single pollination with color, pattern, and texture.  Each chromosome had knobs and other oddities by which to identify it, so that McClintock could study genetics directly through her microscope.  Comparing kernels and chromosomes in this way, she became conversant with jumping genes.
    Somehow each of these geneticists found their true tasks and their soul-mate organisms.  Was it their own luck or divine guidance?