E. Warren to K. Pearson, 12th March 1899.- External URL
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Sent From (Definite): Ernest WarrenSent To (Definite): Karl PearsonDate: 12 Mar 1899
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Holder (Definite): University College London: Special Collections
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Sent fromErnest Warren
12 Mar 1899
Description:
‘Dear Prof. Pearson,
Many thanks for your note re: the relative variability of sexual and parthenogenetic generations.
I am sending a note to the Royal comprising the observations on Daphnia and therein stating that I am about to test the theory on some other parthenogenetic animal.
The Daphnia results certainly tell against Weismann’s views at least in an unmodified form. If I understand Weismann correctly the offspring in a brood produced by parthenogenesis should exhibit little or no variability or as you say drones should be much alike to one another. In the Daphnia the offspring of a parentage of 169.5 thousands possessed a range of variation from 159.5-181.5 while the total range of all the offspring (i.e. of all the 96 individuals) was 159.5-185.5 thousands. Thus although the coeffts. of correlation and regression were respectively .466 and .619 yet the individuals of the same brood showed very considerable variability.
Bees would be good things to measure (- at least so I should think) but there is a difficulty with regard to the origin of the drones. Apparently in a hive if there happens to be a scarcity of drones some of the workers will produced [sic] males parthenogenically!! Thus in any population of drones some may have been produced by parthenogenesis by the Queen & some by the usually barren workers.
With regard to the increase of variability with parthenogenesis. My results apparently show that the S.D. of offspring is greater than that of parents & so with a correlation of .4 the regression is .6 & the parthenogenetic mother acts, so to speak, like a mid-parent. It is this that I hope to test on a new beast. Aphis (the greenfly) seems a favourable creature for the purpose but it is doubtful whether it would be practicable to obtain sexual generations to compare with the parthenogenetic ones. There are about 10 parthenogenetic generations than winged sexual forms are born & these lay eggs which hatch out parthenogenetic females.
I am sincerely sorry that your recovery is so slow.
Yours very faithfully,
E. Warren.
P.S. It is the apparent increase of variability as we pass from one parthenogenetic generation to another that puzzles me. It is very antagonistic to Weismann.’
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Sent toKarl Pearson
12 Mar 1899
Description:
‘Dear Prof. Pearson,
Many thanks for your note re: the relative variability of sexual and parthenogenetic generations.
I am sending a note to the Royal comprising the observations on Daphnia and therein stating that I am about to test the theory on some other parthenogenetic animal.
The Daphnia results certainly tell against Weismann’s views at least in an unmodified form. If I understand Weismann correctly the offspring in a brood produced by parthenogenesis should exhibit little or no variability or as you say drones should be much alike to one another. In the Daphnia the offspring of a parentage of 169.5 thousands possessed a range of variation from 159.5-181.5 while the total range of all the offspring (i.e. of all the 96 individuals) was 159.5-185.5 thousands. Thus although the coeffts. of correlation and regression were respectively .466 and .619 yet the individuals of the same brood showed very considerable variability.
Bees would be good things to measure (- at least so I should think) but there is a difficulty with regard to the origin of the drones. Apparently in a hive if there happens to be a scarcity of drones some of the workers will produced [sic] males parthenogenically!! Thus in any population of drones some may have been produced by parthenogenesis by the Queen & some by the usually barren workers.
With regard to the increase of variability with parthenogenesis. My results apparently show that the S.D. of offspring is greater than that of parents & so with a correlation of .4 the regression is .6 & the parthenogenetic mother acts, so to speak, like a mid-parent. It is this that I hope to test on a new beast. Aphis (the greenfly) seems a favourable creature for the purpose but it is doubtful whether it would be practicable to obtain sexual generations to compare with the parthenogenetic ones. There are about 10 parthenogenetic generations than winged sexual forms are born & these lay eggs which hatch out parthenogenetic females.
I am sincerely sorry that your recovery is so slow.
Yours very faithfully,
E. Warren.
P.S. It is the apparent increase of variability as we pass from one parthenogenetic generation to another that puzzles me. It is very antagonistic to Weismann.’
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