• Y. Imai

      Articles written in Journal of Genetics

    • On a monstrous flower and its linkage in the Japanese morning glory

      K. Miyake Y. Imai

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      The heart leaf (h) and the “Shishi” form (si) are respectively transmitted as recessives to the normal.

      Owing to the incomplete dominance of the H and Si factors the segregating ratios are each a 1 : 2 : 1.

      About 1.2 per cent. of crossover occurs in a linkage between these two factors. By the convenient nature of incomplete dominance calculation of. linkage was directly made with the self-propagated specimens in the hybrid progeny.

      The percentage of crossover is almost equal in the case both of coupling and repulsion.

      The Si factor represents multiple effects on flower and leaf as well as cotyledon.

      The grasped leaf found in the “Shishi” strain is due to the result of the additional effect of a punched factor (u).

    • On the double flowers of the Japanese morning glory

      K. Miyake Y. Imai

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    • The pipy flower ofPharbitis Nil as a mutable character

      Y. Imai B. Kanna

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      1. The pipy flower, which ahs a small tubular corolla, appeared spontaneously by mutation in anF2 pedigree. The character is due to a recessive gene, which is automutable, frequently changing into normal.

      2. The pipy plant produces about 2·9 per cent. of mutated, normal gametes, resulting in 5·9 per cent. heterozygous normal individuals. The lability of pipy causes a marked deficit in the pipy segregates in the heterozygous pedigrees. In addition to this, pipy plants exhibit vegetative mutation to normal, becoming themselves mosaic. The occurrence of mosaics in the pipy plants reaches 17·2 per cent. Vegetative mutation occurs also in the heterozygous normal sporophytes, bearing normal flowers in otherwise heterozygous crinkled flowers.

      3. Bud-variation on the pipy stock appears in three forms, namely, crinkled normal, enlarged pipy, and less-enlarged pipy. The crinkled normal sport has either mutated, normal ecto- and meso-histogens or all normal tissues, the enlarged pipy has normal meso-histogen, and the less-enlarged pipy normal ecto-histogen, the last two at least being periclinal chimeras with heterogeneous tissues.

      In concluding this paper we wish to express our thanks to the Foundation for the Promotion of Scientific and Industrial Research of Japan for the grant from which the expenses incurred in connection with the present investigation were partly defrayed.

    • A probable case of cytoplasmic inheritance in man: A critique of leber’s disease

      Y. Imai D. Moriwaki

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      The cause of Leber’s disease probably lies in abnormal cytoplasm, inheritance being therefore maternal (Lossen’s law). The abnormal cytoplasm continues in the egg of the affected pedigrees from generation to generation, so that all females are carriers of the disease (Kitashima’s law). The disease, in its attack, is stimulated by a sex hormone, especially that secreted by the male. The frequency distribution of the disease therefore differs in the two sexes. In some European, and in the majority of Japanese pedigrees, the proportion of females affected is higher than in the ordinary case, due probably to the higher sensibility of the cytoplasm carried by the particular pedigrees to stimulation of the female hormone, so that transmission of the disease is a case of sex-controlled inheritance. The Chinese case reported by Yang has a different cause, being due to an autosomal dominant gene.

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