Breed "pure" mice with known genotypes that exhibit specific fur and eye colors, and learn how traits are passed on via dominant and recessive genes. Mice can be stored in cages for future breeding, and the statistics of fur and eye color are reported every time a pair of mice breed.
People can definitely end up with both copies of one of their chromosomes coming from a single parent. In fact, it is common enough that geneticists have even given it a name, uniparental disomy