Cookies Policy
X

This site uses cookies. By continuing to browse the site you are agreeing to our use of cookies.

I accept this policy

Find out more here

Skewed Sex-Ratio, Monogeny, and Maternal Sex Determination in Two Geographical Populations of Asellus Aquaticus (L., 1758) (Isopoda)

No metrics data to plot.
The attempt to load metrics for this article has failed.
The attempt to plot a graph for these metrics has failed.
The full text of this article is not currently available.

Brill’s MyBook program is exclusively available on BrillOnline Books and Journals. Students and scholars affiliated with an institution that has purchased a Brill E-Book on the BrillOnline platform automatically have access to the MyBook option for the title(s) acquired by the Library. Brill MyBook is a print-on-demand paperback copy which is sold at a favorably uniform low price.

Access this article

+ Tax (if applicable)
Add to Favorites
You must be logged in to use this functionality

image of Crustaceana

For the great majority of the amphipods and isopods a biased sex ratio is attributed to photoperiod or to micro-organisms present in the cytoplasm of the oocytes. Since monogenous pairs are found in orders and species phylogenetically very far from each other, in order to try and clarify this phenomenon, two geographical populations of Asellus aquaticus (Isopoda) were collected in the Netherlands and in Italy, where the duration of the cold season and the photoperiods are very different. From these parental (P) populations, 200 females and 200 males per population were randomly subsampled and bred under standard conditions of temperature and nutrition. One half of each P generation was subjected to 18 hours light per day, the other to 14 hours light per day. New-born of each pair (laboratory F1) were grown up to differentiation of external sexual characters under the same photoperiod experienced by the parents. Also, hybrid F1 generation, born from mating between the two populations, was conceived in both photoperiods, but, after birth, one half of the new-born was maintained in the same photoperiod in which they were conceived, the other half was grown under the other photoperiod. No significant difference between the sex ratios was found in the two photoperiods, neither between Italian nor between Dutch Asellus. The sex ratio of Dutch F1 is female biased, while it is male biased in Italian Asellus. The female- or male-biased sex ratio can be ascribed to the high proportion of monogenous pairs in which offspring sex ratio is significantly biased towards females (in the Dutch population) and/or in which offspring sex ratio is significantly biased towards males (in the Italian population). On the basis of these results we can rule out the influence of photoperiod in sex determination for this species. The results shown by the hybrids suggest some form of maternal inheritance. In fact, the hybrids' sex ratio as indeed the frequency of pairs breeding one sex alone, was skewed towards the same sex for which the maternal population showed a bias. We therefore consider the possibility of sex determination associated with a cytoplasmic factor (a mitochondrial DNA?), which would inactivate only one of the two sets of genes governing sex determination.

Affiliations: 1: Dpt. Genetica e Biologia Molecolare, University of Rome "La Sapienza", P.le Aldo Moro, 5, I-00185 Rome, Italy

Loading

Full text loading...

/content/journals/10.1163/156854096x01041
Loading

Data & Media loading...

http://brill.metastore.ingenta.com/content/journals/10.1163/156854096x01041
Loading

Article metrics loading...

/content/journals/10.1163/156854096x01041
1996-01-01
2016-12-04

Sign-in

Can't access your account?
  • Tools

  • Add to Favorites
  • Printable version
  • Email this page
  • Subscribe to ToC alert
  • Get permissions
  • Recommend to your library

    You must fill out fields marked with: *

    Librarian details
    Your details
    Why are you recommending this title?
    Select reason:
     
    Crustaceana — Recommend this title to your library
  • Export citations
  • Key

  • Full access
  • Open Access
  • Partial/No accessInformation