DNA content in erythrocyte nuclei of water frogs from a pure Rana esculenta population in Dębki (Gdańsk district, Poland)
✍ Scribed by Maria Ogielska; Krystyna Kazana; Piotr Kierzkowski
- Publisher
- Pensoft Publishers
- Year
- 2008
- Tongue
- English
- Weight
- 468 KB
- Volume
- 77
- Category
- Article
- ISSN
- 0232-5519
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✦ Synopsis
Rana emdenta is a hybridogenetic hybrid between Rnna ridibunda and R a m lessonae. Usually the hybrids, among which diploid and triploid individuals of both sexes were described, live in mixed populations with one of the parental species (L-E or R-E systems). The hybrids also form pure esculentu-esculenta populations (E-E system). 114 individuals from the Baltic Sea region were collected in 1990-1991 and 1998-1999. Blood smears were taken and erythrocyte areas were measured. The erythrocyte area ranged from 318.27 pm2 to 571.82 pm2 and two peaks could be distinguished: 370 pmZ and 460-490 pm?. The smears were then stained according to the Feulgen method and the DNA amount per nucleus was determined by nieasuring the integrated optical density of the nucleus area. The correlation between erythrocyte size and DNA content was relatively high (0.82). Nevertheless, in some cases the erythrocyte size was not a good indicator of DNA content. Specimens had various DNA content and they formed two distinct groups: one with higher and one with lower DNA content. However, we were not able to discriminate the expected two classes of diploid and triploid individuals. The results indicated that the problem of ploidy is complicated, and we cannot rule out the existence of aneuploids or mosaics among hybrids. The problem needs to be elucidated in combination with other methods, especially because it allows measuring the ploidy level in great number of animals without killing them and thus seems to be very useful for population studies.