Controversies The proximity of Mendel's F, progeny data to an incorrect expectation is not as questionable it might seem when viewed in a botanical context Mendel probably sowed more than ten seeds in a space to be occupied by ten plants, then thinned the seedlings to ten to ensure that there were ten F3 progeny from each F2 plant. Indeed, Mendel's description of his method, reported cultivating rather than sowing seeds Had Mendel sown more than ten seeds from each F2 plant, then he could have scored two of the plant traits in seedlings before thinning Differences in stem length, as Mendel noted in his paper, can be easily scored in seedlings a few days after germination Variation for flower and seed-coat color was perfectly correlated with variation for axillary pigmentation in his experiments. Mendel could score F3 plants for the presence or absence of axillary pigmentation as early as two to three weeks after germination Wright (1966)and Beadle(1967)proposed that Mendel might have unconsciously misclassified individuals with questionable phenotypes to favor his expectations o Mendel was careful about misclassification of phenotypes and had mentioned that with a little practice in sorting, however, mistakes are easy to avoid o Mendel identified not only the phenotypes, but also the genotypes of individual seeds through examination of their self-fertilized progeny Mendel might have stopped counting individuals when the numbers were close to the ratios he expected [olby(1985)and Beadle(1967) o The average number of seeds per plant is close to 30(16 590 seeds divided by 550 plants=30 16 seeds per plant from the monohybrid, dihybrid, and trihybrid nts for seed shape and cotyledon color) o Is 30 seeds per plant too low for 19 century pea cultivation? o Dr J. Rasmussen, a pea geneticist wrote to Fisher: " About 30 good seeds per plant is, under Mendel's conditions. o Fairbanks and Rytting(2001)found that average number of seeds per plant was 47.18 among 24 garden-pea varieties grown at the New York Agricultural Experiment Station in Geneva, during 1888(Curtis, 1889) Of the 24 varieties tested, four produced averages of less than 30 seeds In Mendels second letter to Nageli, he referred to his paper as the unchanged reprint of the draft of the lecture mentioned; thus the brevity of the exposition, as is essential for public lecture Fairbanks and rytting(2001)concluded that, although the bias in Mendel's experiments is evident, there are reasonable statistical and botanical explanations for the bias, and insufficient evidence to indicate that Mendel or anyone else falsified the dataControversies 2 The proximity of Mendel's F3 progeny data to an incorrect expectation is not as questionable as it might seem when viewed in a botanical context. • Mendel probably sowed more than ten seeds in a space to be occupied by ten plants, then thinned the seedlings to ten to ensure that there were ten F3 progeny from each F2 plant. Indeed, Mendel's description of his method, reported cultivating rather than sowing 10 seeds. • Had Mendel sown more than ten seeds from each F2 plant, then he could have scored two of the plant traits in seedlings before thinning. o Differences in stem length, as Mendel noted in his paper, can be easily scored in seedlings a few days after germination. o Variation for flower and seed-coat color was perfectly correlated with variation for axillary pigmentation in his experiments. Mendel could score F3 plants for the presence or absence of axillary pigmentation as early as two to three weeks after germination. • Wright (1966) and Beadle (1967) proposed that Mendel might have unconsciously misclassified individuals with questionable phenotypesto favor his expectations. o Mendel was careful about misclassification of phenotypes and had mentioned that "with a little practice in sorting, however, mistakes are easy to avoid". o Mendel identified not only the phenotypes, but also the genotypes of individual seeds through examination of their self-fertilized progeny. • Mendel might have stopped counting individuals when the numbers were close to the ratios he expected [Olby (1985) and Beadle (1967)]. o The average number of seeds per plant is close to 30 (16 590 seeds divided by 550 plants = 30.16 seeds per plant from the monohybrid, dihybrid, and trihybrid experiments for seed shape and cotyledon color). o Is 30 seeds per plant too low for 19th century pea cultivation? o Dr. J. Rasmussen, a pea geneticist wrote to Fisher: "About 30 good seeds per plant is, under Mendel's conditions." o Fairbanks and Rytting (2001) found that average number of seeds per plant was 47.18 among 24 garden-pea varieties grown at the New York Agricultural Experiment Station in Geneva, during 1888 (Curtis, 1889). ƒ Of the 24 varieties tested, four produced averages of less than 30 seeds per plant. • In Mendel'ssecond letter to Nägeli, he referred to his paper as "the unchanged reprint of the draft of the lecture mentioned; thus the brevity of the exposition, as is essential for a public lecture". • Fairbanks and Rytting (2001) concluded that, “although the bias in Mendel's experiments is evident, there are reasonable statistical and botanical explanations for the bias, and insufficient evidence to indicate that Mendel or anyone else falsified the data