Studies on the chromosomes of the rainbow lizard Agama agama agama (L.) with notes on polypoidy in the spermatocytes.

Adegoke, Joseph A.

doi:10.1508/cytologia.53.233

Cited by 4 publications

(3 citation statements)

References 13 publications

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“…Sex determination mode is relatively well studied in a few species from the subfamily Amphibolurinae [7,19], but not in the other five subfamilies (Figure 1), highlighting a significant gap in our understanding of how sex chromosomes evolved in this widespread and chromosomally variable family. [6,17,20,21,24,31,[34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49]. The species of the subfamily Draconinae are distributed over South and Southeast Asia, Agaminae across Africa and Asia, Amphibolurinae across Australia, Papua New Guinea and Southeast Asia, Hydrosaurinae across Papua New Guinea, the Philippines and Indonesia, Leiolepidinae across Southeast Asia and Uromastycinae across Africa and South Asia.…”

Section: Introductionmentioning

confidence: 99%

Cross-Species BAC Mapping Highlights Conservation of Chromosome Synteny across Dragon Lizards (Squamata: Agamidae)

Alam

Altmanová

Prasongmaneerut

et al. 2020

Genes

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Dragon lizards (Squamata: Agamidae) comprise about 520 species in six subfamilies distributed across Asia, Australasia and Africa. Only five species are known to have sex chromosomes. All of them possess ZZ/ZW sex chromosomes, which are microchromosomes in four species from the subfamily Amphibolurinae, but much larger in Phrynocephalus vlangalii from the subfamily Agaminae. In most previous studies of these sex chromosomes, the focus has been on Australian species from the subfamily Amphibolurinae, but only the sex chromosomes of the Australian central bearded dragon (Pogona vitticeps) are well-characterized cytogenetically. To determine the level of synteny of the sex chromosomes of P. vitticeps across agamid subfamilies, we performed cross-species two-colour FISH using two bacterial artificial chromosome (BAC) clones from the pseudo-autosomal regions of P. vitticeps. We mapped these two BACs across representative species from all six subfamilies as well as two species of chameleons, the sister group to agamids. We found that one of these BAC sequences is conserved in macrochromosomes and the other in microchromosomes across the agamid lineages. However, within the Amphibolurinae, there is evidence of multiple chromosomal rearrangements with one of the BACs mapping to the second-largest chromosome pair and to the microchromosomes in multiple species including the sex chromosomes of P. vitticeps. Intriguingly, no hybridization signal was observed in chameleons for either of these BACs, suggesting a likely agamid origin of these sequences. Our study shows lineage-specific evolution of sequences/syntenic blocks and successive rearrangements and reveals a complex history of sequences leading to their association with important biological processes such as the evolution of sex chromosomes and sex determination.

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Section: Introductionmentioning

confidence: 99%

Cross-Species BAC Mapping Highlights Conservation of Chromosome Synteny across Dragon Lizards (Squamata: Agamidae)

Alam

Altmanová

Prasongmaneerut

et al. 2020

Genes

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“…Using such techniques on the DNA of the extant species of Aguma would be useful in studying the phylogenetic relationship in the genus (Agama) on which there has been some inconsistencies (Harris, 1963;Adegoke, 1988).…”

Section: Discussionmentioning

confidence: 99%

Characteristic features of the sonicated DNA of Agama agama agama L. (Reptilia, Agamidae) on hydroxyapatite columns, using mouse DNA as a reference

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Hydroxyapatite column chromatography has been used to study some properties of the extensively sheared DNA of the Rainbow lizard, Agama agama agama. Reassociation studies show that the genome has a Cot1/2 of 370. Approximately 15% of the genome is highly repetitive in nature. This repetitive fraction is resolved into thermally stable and less stable fractions. The stable fraction has a base composition of 47% GC, higher than the 40.2% GC for the native DNA. This stable fraction is believed to be of recent origin. Chromatography of the total DNA of the lizard with linear gradients of phosphate buffer containing 1 M urea resolves it into two components which were shown by thermal fractionation, also in the presence of 1 M urea, to vary in base composition. This behaviour may be characteristic of reptilian genomes and may be used as a basis for studying the structural organisation of the reptilian genome.

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“…The subfamily Agaminae includes a group of genera closely related to Trapelus with synapomorphic karyotypes (such as Agama Daudin, 1802), as well as the sister lineage which includes the genus Laudakia (sensu lato) with the ancestral iguanian karyotype, and the genus Phrynocephalus , which experienced fissions of the macrochromosomes apparently independently from the Trapelus + Agama clade. To date, meiotic chromosomes are known only for Agama agama (Linnaeus, 1758) [Adegoke, 1988] and a small number of the Phrynocephalus species [Manilo and Golubev, 1994;Manilo, 2000], but the poor quality of the presented microphotographs does not allow accurate counting of the chiasmata. All these lizards should be studied further to draw more general conclusions.…”

Section: Male Meiotic Recombination In the Steppe Agamamentioning

confidence: 99%

Male Meiotic Recombination in the Steppe Agama, <b><i>Trapelus sanguinolentus</i></b> (Agamidae, Iguania, Reptilia)

Lisachov

Tishakova

Tsepilov

et al. 2019

Cytogenet Genome Res

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Meiotic recombination rates and patterns of crossover distributions along the chromosomes vary considerably even between closely related species. The adaptive significance of these differences is still unclear due to the paucity of empirical data. Most data on recombination come from mammalian species, while other vertebrate clades are poorly explored. Using immunolocalization of the protein of the lateral element of the synaptonemal complex (SYCP3) and the mismatch-repair protein MLH1, which marks mature recombination nodules, we analyzed recombination rates and crossover distribution in meiotic prophase chromosomes of the steppe agama (Trapelus sanguinolentus, Agamidae, Acrodonta, Iguania) and compared them with data obtained for the genus Anolis (Dactyloidae, Pleurodonta, Iguania). We found that, despite a smaller genome size, the total SC length and the MLH1 focus number per cell are much higher in the agama than in the anoles. The distributions of the MLH1 foci in the agama are multimodal in larger chromosomes and bimodal in smaller chromosomes without a significant centromere effect, resembling the patterns known for birds. A possible relationship between karyotype remodeling and the evolution of recombination in Iguania is discussed.

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Studies on the chromosomes of the rainbow lizard Agama agama agama (L.) with notes on polypoidy in the spermatocytes.

Cited by 4 publications

References 13 publications

Cross-Species BAC Mapping Highlights Conservation of Chromosome Synteny across Dragon Lizards (Squamata: Agamidae)

Cross-Species BAC Mapping Highlights Conservation of Chromosome Synteny across Dragon Lizards (Squamata: Agamidae)

Characteristic features of the sonicated DNA of Agama agama agama L. (Reptilia, Agamidae) on hydroxyapatite columns, using mouse DNA as a reference

Male Meiotic Recombination in the Steppe Agama, <b><i>Trapelus sanguinolentus</i></b> (Agamidae, Iguania, Reptilia)

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