抄録
KAWAKAMI J, found diploid twins (2ni2 n) aruong F2 generation of hybrids in wheat in 1933 and 1934. Genetical constitutions of tbese twins were studied experimentally and the numbers of twins which have different constitution were calculated. HATAMURA M. co-oiperated with:him explainihg statistically the mechanism of occurrence. of these twins: The authors postulate the following m:echanism : (1) In both of the male and female gametes of F1 hybrids which will produce twins, domi hant genes studied are fundtional just like they have been' in the ratio of p, '(1-p) agaainst recessive ones by some reason or others. ( 2 ) In the embryo sac, three nuclei, an egg nucleus and probably two synergids, are able to be fertilized respectively by one nucleus o.f male ga.metes penetrated therein, producing at most three zygotes . These three zygotes combine' independently, resulting in 2n individua.Is, 2 n-2 n twins or 2 n-2 n-2 n triplets. ( 3 ) Two nuclei of the male gamete which may penetrate flrst into the embryo sac will fertilize two of the available femaie nuclei. One nucleus of another n), ale gamete follawing will fertiliz6 the remaining one available fem, ale nucleus . Probability, p that the gamete contains the func tional dominant ene was estimated by the maximum likelihood method . Applying this p, theoretical numbers of 2 n-2 n twins which have different genetical constitutions were calculaed . x2LTests did not provide eyidenc that the hypothesis above mentidned should be rejected .
