Evolution of Mitochondrial Relationships and Biogeography of Palearctic Green Toads (Bufo Viridis Subgroup) With Insights in Their Genomic Plasticity

TLDR: A cytogenetic dataset from Central Asia is put in a molecular framework and phylogenetic and demographic methods are applied to data from the entire Palearctic range to study the mitochondrial relationships of diploids to infer their phylogeography and the maternal ancestry of polyploids.

About: This article is published in Molecular Phylogenetics and Evolution.The article was published on 2006-12-01 and is currently open access. It has received 153 citations till now. The article focuses on the topics: Phylogeography.

Figures

Fig. 1. Geographic range of the Bufo viridis subgroup with sampling localities and sites of oldest known fossils of the B. viridis subgroup. See legend a range limits after Balletto et al. (1985), Bons and Geniez (1996), Gasc et al. (1997), Borkin (1999), Kuzmin (1999), Schleich et al. (1996), and Stöck et al. (2

Fig. 4. Parsimony-based haplotype network obtained with the program TCS 1.18 using d-loop sequences of groups A and B of the tree shown in Fig. 3 (left). Gray ellipsoids represent 2n, white rectangles 4n and white triangles indicate 3n toads. Black dots represent hypothetical haplotypes not sampled. Ploidy levels (e.g. 4n), sample ID (max. three digits, see Appendix A), and locality ID as in (Figs. 1 and 2).

Table 1 Average divergence ces

Fig. 2. Geographic range of the Bufo viridis subgroup in High Asia with sampling localities. See legend and Appendix A for locality IDs.

Frequently asked questions

Q1. What are the contributions mentioned in the paper "Evolution of mitochondrial relationships and biogeography of palearctic green toads (bufo viridis subgroup) with insights in their genomic plasticity" ?

The authors study the mitochondrial relationships of diploids to infer their phylogeography and the maternal ancestry of polyploids. The authors report another potential case of bisexual triploid toads ( B. zugmayeri ). Identical d-loops in diploids and tetraploids from Iran and Turkmenistan, which diVer in morphology, karyotypes and calls, suggest multiple origins and retained polymorphism and/or hybridization. 

Q2. What are the future works in "Evolution of mitochondrial relationships and biogeography of palearctic green toads (bufo viridis subgroup) with insights in their genomic plasticity" ?

The authors also identify regions with close geographic proximity or overlap of major mtDNA phylogroups that should be the focus of future studies. 

Q3. How many steps were used to ensure stability of estimates?

Repeated analyses to ensure stability of estimates were run with random seeds, 10 short Monte Carlo chains of 4000 steps, and Wve long chains of 20,000 steps. 

Q4. What was used for rooting the d-loops tree?

While B. raddei served as the “outgroup” taxon for the phylogenetic analyses of the d-loops, B. regularis was used for rooting the “ND+ tRNAs” tree (see below). 

Q5. How many other divergence times were estimated using this rate estimate?

Using this rate estimate, other divergence times among pairwise regional groups were estimated with D ( b¡ w)/2 , where is the divergence time, is the DNA substitution rate per locus per generation, b is the average number of pairwise diVerences between sampled populations, and w is the average number of pairwise diVerences within populations (Nei and Li, 1979). 

Q6. What is the earliest diverged western Himalayan B. latastii?

The earliest diverged western Himalayan B. latastii (2n-I) and its southern Iranian sister species B. surdus represent descendents of an Upper Oligocene/Lower Miocene split (Table 1) from the MRCA with African (2nIII) and all other green toad clades. 

Q7. How did the authors estimate the age of population expansion for green toad groups?

The authors estimated the age of population expansion for green toad groups as found in a certain geographical region using Fluctuate (Kuhner et al., 1998) by obtaining maximum likelihood estimates for (2N ; is DNA substitution rate per site per generation, N is the current female eVective population size) and g (the historical exponential growth parameter). 

Q8. What is the d-loopsequence of B. regularis?

In representatives from most clades (and ploidy levels), as revealed from analyses of d-loopsequences (see below), as well of B. calamita, B. brongersmai, B. bufo and B. regularis, the authors sequenced an additional 1100 bases of mtDNA extending from ND1 through the tRNAIle, tRNAGln, and tRNAMet genes to ND2 (termed “ND + tRNAs” here), as described by Macey et al. (1998a,b).