Geneticists use a standard shorthand to express traits using letters of the alphabet

Geneticists use a standard shorthand to express traits using letters of the alphabet

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Geneticists use a standard shorthand to express traits using letters of the alphabet,  upper case for dominant, lower case for recessive. Red color, for example, might be R  or r so a homozygous dominant individual would be RR, a homozygous recessive  individual, rr and a heterozygous individual Rr.  Crosses between parents that differ in a single gene pair (such as those that Mendel  made) are called monohybrid crosses (usually TT and tt). Crosses that involve two traits  are called dihybrid crosses. Symbols are used to depict the crosses and their offspring.  The letter P is used for the parental generation and the letter F for the filial or offspring  generation. F 1  is the first filial generation, F 2  the second, and so forth.  What kinds of crosses did Mendel make to conclude that factors/genes segregate? First 
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Unformatted text preview: of all, he made certain that the plants that he planned to use in the experiment were pure line for the traitthat is, that they bred true for the trait for two or more years. (Peas are self-pollinated so he simply grew the plants and examined their offspring.) Other experimenters omitted this step, which confounded their results. Mendel then made a series of monohybrid crosses for each of the seven traits he had identified using parents of opposite traitstall (TT) vs. dwarf (tt), yellow seed (YY) vs. green (yy) seed, round seed (RR) vs. wrinkled (rr), and so forth. (He, of course, did not symbolize them with letters, but he did know that seeds from his tall pure-line plants would always produce tall plants, seeds from the dwarfs would always produce dwarf plants, and so on.)...
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