Genetic polymorphism in population of giant toad Bufo marinus Linn. (AMphibia Bufonidae) in the Philippines based on chromosome banding and protein electro phoresis

Date

3-1995

Abstract

Three populations of giant toad Bufo marinus Linn. from three areas in the Philippines were surveyed for polymorphism based on chromosome banding pattern and electrophoretic analyses. Karyotype analysis revealed that the toad possesses a diploid (2n) chromosome complement equal to 22. The mean relative lengths and centromeric indices of the 11 chromosome pairs in three population of B. marinus did not vary significantly using Analysis of Variance. Chromosomes 5 and 6 exhibited significant variation in the arm ratio. Chromosomes were grouped into three categories: Group A ( 5 pairs of large chromosomes), Group B (4-5 pairs of intermediate chromosomes) and Group C (1-2 pairs of small chromosomes). Except for chromosome 4 which has submedian centromere, all other chromosomes have median centromeres. No structural or numerical chromosomal. abnormality was encountered. The secondary constriction observed as achromatic region in the short arm of chromosome 7 was not always distinct and visible. Absence of C-banding was observed in all chromosomes. Silver nitrate staining yielded invariant silver blocks in the nucleolus organizing region (AgNOR) in the short arm of chromosome 7.

Using starch gel electrophoresis, eight blood proteins (encoded by 12 presumptive loci) such as albumin, transferrin, three plasma proteins, erythrocyte esterases and malate dehydrogenase and hemoglobin were analyzed. A wide range of intrapopulation genetic variation was revealed by the indices average heterozygosity, proportion of polymorphic loci and average number of alleles per locus. The Mindanao toad population was highly variable followed by the Luzon group. The Visayas population, on the other hand, showed the least variability. Estimates of Nei's and Hillis' genetic identity and distance showed that the Luzon and Mindanao populations share many alleles in common and are therefore more closely related. Consequently, greatest genetic divergence exists between the Luzon and Visayas populations.

Document Type

Dissertation

Degree

Doctor of Philosophy in Genetics

College

Graduate School (GS)

Adviser/Committee Chair

Adelina A. Barrion

Committee Member

Ayolani V. De Lara, Dario C. Sabularse, Rita P. Laude, Darshan S. Brar

Language

English

LC Subject

Bufo marinus

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

LG 996 1995 G2 D69

Notes

Doctor of Philosophy (Genetics)

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