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Population admixture and high larval viability among urban toads
Kazuko Hase1, Naruo Nikoh, Masakazu Shimada
1Department of General Systems Studies, The University of Tokyo Meguro, Tokyo, 153-8902, Japan.
Ecology and Evolution
|June 22, 2013
Summary
Introduced Japanese common toads (Bufo japonicus japonicus) dominate urban Tokyo populations, increasing genetic variation and larval survival rates through hybridization with native Bufo japonicus formosus.
Area of Science:
- Evolutionary Biology
- Conservation Biology
- Genetics
Background:
- Population admixture from secondary contact presents conservation challenges.
- Urban Tokyo hosts an admixture of native Bufo japonicus formosus and introduced Bufo japonicus japonicus.
Purpose of the Study:
- To evaluate genetic disturbance in the admixed toad population in Tokyo.
- To assess the impact of introgressive hybridization on toad fitness.
Main Methods:
- Analysis of mitochondrial DNA (mtDNA) and seven microsatellite loci genotypes.
- Morphological assessments of toad populations within and outside Tokyo.
Main Results:
- Introduced Bufo japonicus japonicus genotype dominates six local populations in the Tokyo admixture zone.
- Evidence of past introgressive hybridization between native and nonnative subspecies.
- Significantly higher average larval survival rate in Tokyo compared to outside the admixture zone.
Conclusions:
- Introduced toads have significantly altered the genetic landscape of Tokyo's common toad population.
- Introgressive hybridization appears to be increasing toad fitness in urban Tokyo.
- Artificial secondary contact has led to both genetic disturbance and potential fitness benefits.
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01:24Testing a Claim about Population Proportion
A complete procedure for testing a claim about a population proportion is provided here.
There are two methods of testing a claim about a population proportion: (1) Using the sample proportion from the data where a binomial distribution is approximated to the normal distribution and (2) Using the binomial probabilities calculated from the data.
The first method uses normal distribution as an approximation to the binomial distribution. The requirements are as follows: sample size is large...
There are two methods of testing a claim about a population proportion: (1) Using the sample proportion from the data where a binomial distribution is approximated to the normal distribution and (2) Using the binomial probabilities calculated from the data.
The first method uses normal distribution as an approximation to the binomial distribution. The requirements are as follows: sample size is large...