The inheritance of wing colour and pattern in the lepidopterous genusTephrosia (Ectropis) with an account of the origin of a new allelomorph
Further investigations into the inheritance of melanism in the interspecific crosses betweenTephrosia crepuscularia var.delamerensis female andT. bistortata male reveal, as previously, a failure in the 3:1 ratio in theF 2 generation of such hybrids.
Unlike what occurred in the early cross, no great spread of variation was encountered in the F2 insects.
Instead of types and melanics the F2 brood included types, streaks (mosaics) and melanics.
The character “streak,” when tested by means of breeding experiments, proved to form, with melanism and type, a series of multiple allelomorphs with three members.
Streak is dominant to type and recessive to melanism.
This character originated through a degradation of the gene for melanism during interspecific crossing.
Unit-characters are therefore not constant under all conditions.
In the cross betweenbistortata female andcrepuscalaria var.delamerensis male, and others in which this hybrid was concerned, in back crosses and other broods involvingF 1 melanic (crepuscularia var.delamerensis ♀ ×bistoriata ♂) males, and in complex crosses in which the true melanics of theF 2 (crepuscularia var.delamerensis ♀ ×bistortata ♂) participated, the inheritance of melanism was of the usual simple Mendelian type.
Certain back crosses between (crepuscularia var.delamerensis ♂ ×bistortata ♀) females andbistortata males gave rise to extremely aberrant ratios.
KeywordsGerm Cell Primordial Germ Cell Female Total Wing Colour Complex Cross
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- Baur, E. “Untersuchungen über die Vererbung von Chromatophorenmerkmalen beiMelandrium, Antirrhinum undAquilegia.”Zeit. für indukt. Abst.- und Vererbungslehre, Vol. iv. p. 81 (1911).Google Scholar
- Castle, W. E. Genetic Studies of Rats and Rabbits. Washington (1922).Google Scholar
- Harrison, J. W. H. “The Inheritance of Melanism in the GenusTephrosia (Ectropsis) with some Consideration of the Inconstancy of Unit Characters under Crossing.”Journ. of Genetics, Vol. x. No. 1 (1920).Google Scholar
- Hegner, R. “Germ Cell Determinants and their Significance.”Amer. Nat. Vol. xlv. (1911).Google Scholar
- -. “Studies on Germ Cells. I. The History of Germ Cells in Insects with Special Reference to the Keimbahn Determinants.”Journ. of Morph. Vol. xxv. No. 3 (1914).Google Scholar
- Nilsson-Ehle, H. “Kreuzungsuntersuchungen an Hafer und Weizen.”Univ. Arskrift, Lund. (1909).Google Scholar
- Onslow, H. “Inheritance of Wing Colour in Lepidoptera. II. Melanism inTephrosia consonaria.” Journ. of Genetics, Vol. ix. No. 1 (1919).Google Scholar
- -. “Inheritance of Wing Colour in Lepidoptera. III. Melanism inBoarmia consortaria.” Ibid. Vol. ix. No. 4 (1920).Google Scholar
- Punnett, R. C. “On a Case of Patching in the Flower Colour of the Sweet Pea (Lathyrus odoratus).”Journ. of Genetics, Vol. xii. No. 3 (1922).Google Scholar
- Shull, G. H. “Duplicate Genes for Capsule Form inCapsella Bursa-pastoris.” Zeit. für indukt. Abst.- und Vererbungslehre, Vol. xii. (1914).Google Scholar