Determination and differentiation of sex in Pacific salmon
department or school: Science, Faculty of
department or school: Zoology, Department of
data provider: DSpace
degree campus: UBCV
creator: Robertson, James Grant
issued: 2012-03-19T23:40:02Z
issued: 1951
related degree: Master of Arts - MA
degree grantor: University of British Columbia
description: Chum salmon embryonal discs were smeared and the cells stained with acetocarmine (60° C.) for chromosome content. Thirty-eight chromosomes (granular, sigmoid, and j-shaped) were counted, but the number was not considered absolute. The presence of sex chromosomes could not be established. Chromosomes in cells of differentiating gonads showed such excessive clumping that a count could not be made. Sex differentiation was followed in chum salmon. Sections from alevins (three weeks old) showed the gonads to be indifferent. Isolated nests of germ cells appeared which eventually formed a continuous cord (five weeks). At nine weeks the primordial ovary developed oocytes and in the succeeding week formed an endovarial canal. At this time the testis was first recognized (ten weeks). It was a small compact organ containing spermatogonia. Up to the final examination (fifteen weeks) the ovary showed no new structures excepting a prominent vena commites anteriad, while the testis retained its primitive features. The sex of pink and chum salmon fry migrants were shown by dissection. Ultraviolet light and temperature treatment of developing chum, pink, and sockeye embryos did not show that these factors would influence the sex ratio. Temperature data were decidedly inconclusive. An equal distribution of the sexes in pink and chum fry and sockeye smolts was found in data compiled from migrant runs at Port John, B. C. It is suggested that precocious male sockeye mature in the sea. The sex ratios at stages in the life history of the pink salmon are presented to show that there had occurred a natural sea mortality of 40.2 percent.
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/41536
note: DETERMINATION AND DIFFERENTIATION OF SEX IN PACIFIC SALMON by JAMES GRANT ROBERTSON (isi Or 4 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF-ARTS i n the Department of Zoolpgy We accept t h i s t h e s i s as conforming to the standard r e q u i r e d from candidates f o r the degree o f MASTER OF ARTS. Members o f the Department o f Zoology THE UNIVERSITY OF BRITISH COLUMBIA A p r i l , 1951 ABSTRACT Chum salmon embryonal d i s c s were smeared and the c e l l s s t a i n e d with acetocarmine (60° C.) f o r chromosome content. T h i r t y - e i g h t chromosomes ( g r a n u l a r , sigmoid,and j-shaped) were counted, but the number was not c o n s i d e r e d a b s o l u t e . The presence o f sex chromosomes c o u l d not be e s t a b l i s h e d . Chromosomes i n c e l l s o f d i f f e r e n t i a t i n g gonads such showed A e x c e s s i v e clumping t h a t a count could not be made. Sex d i f f e r e n t i a t i o n was f o l l o w e d i n chum salmon. S e c t i o n s from a l e v i n s (three weeks old) showed the gonads to be i n d i f f e r e n t . I s o l a t e d n e s t s o f germ c e l l s appeared which e v e n t u a l l y formed a continuous c o r d ( f i v e weeks). At n ine weeks the p r i m o r d i a l ovary developed oocytes and i n the succeeding week formed an e n d o v a r i a l c a n a l . At t h i s time the t e s t i s was f i r s t r e c o g n i z e d (ten weeks). I t was a s m a l l compact organ c o n t a i n i n g spermatogonia. Up to the f i n a l examination ( f i f t e e n weeks) the ovary showed no new s t r u c t u r e s e x c e p t i n g a prominent vena commites a n t e r i a d , w h ile the t e s t i s r e t a i n e d i t s p r i m i t i v e f e a t u r e s . The sex o f pink and chum salliion f r y migrants were shown by d i s s e c t i o n . U l t r a v i o l e t l i g h t and temperature treatment of developing chum, pink, and sockeye embryos d i d not show: that, these f a c t o r s…
has type: Thesis/Dissertation
is shown at: 10.14288/1.0106906
language: eng
degree discipline: Zoology
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
scholar level: Graduate
type: Text
identifier URI: http://hdl.handle.net/2429/41536