INCIDENCE AND ORIGIN QF ANDROGENETIC MALES IN X-RAYED HABROBRACON EGGS

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Abstract
When eggs are x-rayed in first meiotic metaphase and fertilized by untreated sperm, 1.57% develop into normal, fertile, haploid, androgenetic males. M.L.D. for egg nucleus is about 2400 r, for androgenesis about 54,000 r. Of 291 eggs studied cytologically 3 showed cleavage of sperm nucleus alone, 3 others suggested incipient androgenesis, a maximum of 6 or 2.04%. This does not differ significantly from 1.57% of androgenetic adults and indicates that androgenetic larvae resemble controls in viability. Cytoplasmic resistance to x-rays is, therefore, more than 20 times that of the chromosomes in this stage. Chromatin bridges in meiotic division H following irradiation in metaphase I occasionally retard the egg nucleus to such a degree that cleavage of sperm occurs without it. Cytological drawings illustrate this.
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