Graduate Program in Botany, Department of Biology, Universidade Federal Rural de Pernambuco, Rua Dom Manoel de Medeiros, s/n, Dois Irmãos, Recife, Pernambuco, 52171-900, Brazil.
Laboratory of Cytogenetics and Evolution of Plants, Department of Botany, Universidade Federal de Pernambuco, Av. Professor Moraes Rego s/n, Cidade Universitária, Recife, PE, 50670-901, Brazil.
Protoplasma. 2019 May;256(3):805-814. doi: 10.1007/s00709-018-01334-2. Epub 2019 Jan 3.
The clade ACPT (Anacampserotaceae, Cactaceae, Portulacaceae, and Talinaceae) is the most diverse lineage of the subordem Cactineae. The relationships between these families are still uncertain, with different topologies suggested by phylogenetic analyses with several combinations of markers. Different basic numbers (x) have been suggested for each family and for the subord, often in a contestable way. Comparative cytogenetic has helped to understand the evolutionary relationships of phylogenetically poorly resolved groups, as well as their mechanisms of karyotype evolution. The karyotype evolution in representatives of Cactineae was analyzed, focusing on the ACPT clade, through the analysis of chromosome number in a phylogenetic bias. The phylogeny obtained showed a well-resolved topology with support for the monophyly of the five families. Although a chromosomal number is known for less than 30% of the Cactineae species, the analyses revealed a high karyotype variability, from 2n = 8 to 2n = 110. The analysis of character reconstruction of the ancestral haploid numbers (p) suggested p = 12 for Cactineae, with distinct basic numbers for the clade family ACPT: Cactaceae and Montiaceae (p = 11), Talinaceae (p = 12), and Anacampserotaceae and Portulacaceae (p = 9). Talinaceae, Anacampserotaceae, and Cactaceae were stable, while Portulaca and Montiaceae were karyotypically variable. The chromosome evolution of this group was mainly due to events of descending disploidy and poliploidy. Our data confirm that the low phylogenetic resolution among the families of the ACPT clade is due to a divergence of this clade in a short period of time. However, each of these families can be characterized by basic chromosome numbers and unique karyotype evolution events.
ACP 分支（番杏科、仙人掌科、马齿苋科和半日花科）是仙人掌亚目下最多样化的谱系。这些科之间的关系仍然不确定，不同的系统发育分析结果表明，不同的标记组合具有不同的拓扑结构。不同的基本染色体数（x）被建议用于每个科和亚目，而且往往存在争议。比较细胞遗传学有助于理解系统发育上分辨率较低的群体的进化关系及其核型进化的机制。通过对系统发育偏差中的染色体数目进行分析，研究了仙人掌科代表种的核型进化，重点关注 ACP 分支。获得的系统发育树拓扑结构得到很好的解析，支持五个科的单系性。尽管仙人掌科不到 30%的种的染色体数目已知，但分析显示其核型具有高度的变异性，从 2n=8 到 2n=110。对祖先单倍体数（p）的特征重建分析表明，仙人掌科的 p=12，ACP 分支的科具有不同的基本染色体数：仙人掌科和马齿苋科（p=11），半日花科（p=12），番杏科和马齿苋科（p=9）。半日花科、番杏科和仙人掌科是稳定的，而马齿苋科和马齿苋科则具有核型变异性。该组的染色体进化主要是由于下降的非整倍体和多倍体事件引起的。我们的数据证实，ACP 分支科之间的系统发育分辨率较低是由于该分支在短时间内发生了分歧。然而，这些科中的每一个都可以通过基本染色体数和独特的核型进化事件来表征。
