Record Details
Field | Value |
---|---|
Title | Crossing-over in a reversed acrocentric attached-X chromosome of Drosophila melanogaster |
Names |
Gethmann, Richard Charles
(creator) Mohler, James D. (advisor) |
Date Issued | 1966-08-08 (iso8601) |
Note | Graduation date: 1967 |
Abstract | The frequency of exchanges was measured in a reversed acrocentric compound X chromosome that is deficient for interstitial heterochromatin. Previous studies on similar chromosomes containing interstitial heterochromatin have demonstrated a very low frequency of single exchanges, and high frequencies of the double and no exchange classes. It has been postulated that this abnormal distribution of exchanges is due to the interstitial heterochromatin that is part of the compound. X's structure. The critical test of this explanation has not been done previously and is now provided by the present study. Because the reversed acrocentric is lethal in the absence of the missing heterochromatin, duplications were used to cover the deficiency. Thus, the heterochromatin is present within the genome, but as a separate chromosome. Three structurally different duplications were used. The results were as predicted by the explanation, the frequency of single exchanges is high, and the distribution of the exchanges is like that of free X chromosomes. There was no difference in the effect of the three duplications upon the exchange patterns. |
Genre | Thesis/Dissertation |
Topic | Drosophila melanogaster |
Identifier | http://hdl.handle.net/1957/47813 |