A Caltech Library Service

A Genetic and Cytological Analysis of a Tandem Duplication and its Included Loci in Drosophila melanogaster


Lewis, Edward B. (1942) A Genetic and Cytological Analysis of a Tandem Duplication and its Included Loci in Drosophila melanogaster. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/7W60-4740.



Two loci, Star and asteroid, in the second chromosome of D. melanogaster were found to be extremely closely linked with an estimated standard map distance of 0.01 to 0.04 unit. It was demonstrated that these two loci are included in the 21 E. 1-2 doublet structure of the salivary gland chromosomes. Not only do the Star and asteroid mutants affect the eye in a similar way, but they also show position effects depending on how they are distributed between the two chromosomes. An interpretation of the observed phenomena is made in terms of a naturally occurring repeat in the chromosomes.

The Star Duplication is a tandem repeat in direct order for the four bands, 21 D 3, 4 and 21 E 1-2. It includes the Star and asteroid loci and with the use of mutants at these loci as markers. it has been possible to study unequal crossing over in females heterozygous as well as homozygous for the duplication. The genetic composition of the Star Duplication has been varied in ten distinct ways; the results indicate that there is probably a position effect exerted on the asteroid locus 1n the left section of the duplication causing the originally present asteroid change to act like a reversion to normal. It is likely that there is little or no position effect exerted by the Star and asteroid 1oci in one section on those loci in the other section.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:Biology
Degree Grantor:California Institute of Technology
Major Option:Biology
Awards:The Nobel Prize in Physiology or Medicine, 1995.
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Sturtevant, Alfred Henry
Group:Nobel Prize
Thesis Committee:
  • Unknown, Unknown
Defense Date:1 January 1942
Additional Information:The Nobel Prize in Physiology or Medicine 1995 was awarded jointly to Edward B. Lewis, Christiane Nüsslein-Volhard and Eric F. Wieschaus "for their discoveries concerning the genetic control of early embryonic development."
Record Number:CaltechETD:etd-10172002-112502
Persistent URL:
Related URLs:
URLURL TypeDescription Prize announcement (Physiology or Medicine, 1995)
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:4120
Deposited By: Imported from ETD-db
Deposited On:17 Oct 2002
Last Modified:06 Oct 2020 01:15

Thesis Files

PDF - Final Version
See Usage Policy.


Repository Staff Only: item control page