Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Letter
  • Published:

Maintenance of Heterozygosity in a Homothallic Species of the Neurospora tetrasperma Type

Abstract

IN the homothallic ascomycete Neurospora tetrasperma, two nuclei are normally included in each ascospore, one of mating type A and one of mating type a. N. tetrasperma is therefore normally a dikaryon and heterozygous for the Aa factors. It is interesting to note that the inclusion of an A and an a nucleus in one ascospore leads to the maintenance of heterozygosity of other factors not on the same chromosome but segregating at the same time as the Aa factors. A factor segregates at the first meiotic division if there has been no crossing-over between the factor and the centromere of the chromosome on which it is placed. If there has been such crossing-over the factor segregates at the second division. A factor placed about fifty crossover units from the centromere would be expected to show 100 percent second division segregation, apart from the effect of double cross-overs.

This is a preview of subscription content, access via your institution

Access options

Rent or buy this article

Prices vary by article type

from$1.95

to$39.95

Prices may be subject to local taxes which are calculated during checkout

Similar content being viewed by others

References

  1. Dodge, B. O., Schmitt, B. Mary, and Appel, Anita, Proc. Amer. Phil. Soc., 89 4, 575 (1945).

    Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Rights and permissions

Reprints and permissions

About this article

Cite this article

SANSOME, E. Maintenance of Heterozygosity in a Homothallic Species of the Neurospora tetrasperma Type. Nature 157, 484–485 (1946). https://doi.org/10.1038/157484c0

Download citation

  • Issue Date:

  • DOI: https://doi.org/10.1038/157484c0

This article is cited by

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.

Search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing