The study presents a comprehensive analysis of human centromeres, revealing significant variation and evolution in their structure and function. Using long-read sequencing, researchers fully sequenced and assembled centromeres from a second human genome, comparing them to the finished reference genome. They found that centromeres show a 4.1-fold increase in single-nucleotide variation and up to 3-fold in size differences. The study also identified new α-satellite higher-order repeats (HORs) that complicate alignment and reveal differences in kinetochore position. Comparative analyses of centromeres from chimpanzee, orangutan, and macaque genomes showed a nearly complete turnover of α-satellite HORs, with species-specific changes. Phylogenetic reconstruction supports limited recombination between centromere arms and indicates a monophyletic origin for new α-satellite HORs. Advances in long-read sequencing and assembly algorithms have enabled complete centromere assembly, aided by the use of a complete hydatidiform mole cell line. Despite these advances, centromeres remain challenging to sequence and assemble. The study highlights the diversity and rapid evolution of human centromeres, with α-satellite DNA being the main component. The research underscores the centromere paradox, where centromeric DNA and proteins evolve rapidly despite their essential role in chromosome segregation. The study also reveals that centromeres have different evolutionary trajectories and mutation rates, with some showing saltatory amplification of α-satellite HORs. The findings suggest that mechanisms other than simple unequal crossover may drive the spread of novel α-satellite HORs, and that centromeric DNA can mutate multiple orders of magnitude faster than unique DNA. The study emphasizes the need for further research to understand the mechanisms shaping these rapidly evolving regions of the genome.The study presents a comprehensive analysis of human centromeres, revealing significant variation and evolution in their structure and function. Using long-read sequencing, researchers fully sequenced and assembled centromeres from a second human genome, comparing them to the finished reference genome. They found that centromeres show a 4.1-fold increase in single-nucleotide variation and up to 3-fold in size differences. The study also identified new α-satellite higher-order repeats (HORs) that complicate alignment and reveal differences in kinetochore position. Comparative analyses of centromeres from chimpanzee, orangutan, and macaque genomes showed a nearly complete turnover of α-satellite HORs, with species-specific changes. Phylogenetic reconstruction supports limited recombination between centromere arms and indicates a monophyletic origin for new α-satellite HORs. Advances in long-read sequencing and assembly algorithms have enabled complete centromere assembly, aided by the use of a complete hydatidiform mole cell line. Despite these advances, centromeres remain challenging to sequence and assemble. The study highlights the diversity and rapid evolution of human centromeres, with α-satellite DNA being the main component. The research underscores the centromere paradox, where centromeric DNA and proteins evolve rapidly despite their essential role in chromosome segregation. The study also reveals that centromeres have different evolutionary trajectories and mutation rates, with some showing saltatory amplification of α-satellite HORs. The findings suggest that mechanisms other than simple unequal crossover may drive the spread of novel α-satellite HORs, and that centromeric DNA can mutate multiple orders of magnitude faster than unique DNA. The study emphasizes the need for further research to understand the mechanisms shaping these rapidly evolving regions of the genome.