Characterization and Amplification of Retrotransposable Elements Platy-1 and Alu in the Cebidae Lineage of Platyrrhine Primates

Alu mobile elements are much more than “junk DNA”. Inherent properties such as high copy number, small ~300 bp size, and their nearly homoplasy-free nature make these elements particularly useful in resolving primate phylogenies. In addition, shared sequence features and identity with the Alu element allow for discovery of new SINE retrotransposons, such as the Platyrrhine-limited Platy-1 element. Building on previous research of subfamily analysis, the Platy-1 and Alu elements can be used not only to explore the controversial New World monkey (NWM) phylogeny, but also the mode and tempo of their amplification in different primate genera and species. Chapter 2 explores the amplification of the NWM-limited Platy-1 element. While a large expansion of Platy-1 elements was observed in the marmoset genome, the same cannot be said for the capuchin monkey, squirrel monkey and owl monkey genomes. Of these three genomes, only the owl monkey genome contained evidence of Platy-1 mobilization as shown by the presence of polymorphic (for insertion presence/absence) Platy-1 insertions, low percent divergence values, and the emergence of two new Platy-1 subfamilies. However, there were too few phylogenetically informative Platy-1 insertions to resolve the controversial Cebidae NWM phylogeny. Chapter 3 characterizes the use of the polyDetect pipeline mapping short sequence reads to a reference genome for detecting shared Alu elements that could resolve the NWM phylogeny. However, the short homology provided by the reads was not enough to accurately predict shared Alu insertions of these four NWM genera that have diverged by ~20 million years. Chapter 4 explores not only using longer stretches of identity/homology in the hope of accurately detecting shared Alu insertions, but also analyzes Alu subfamily evolution to resolve the Cebidae NWM phylogeny. A largely congruent network analysis and Bayesian phylogenetic tree were generated as well as Alu alignments, all suggesting that the branching pattern of marmoset, owl monkey, squirrel monkey and capuchin monkey starts with marmoset as the most basal of these four Cebidae NWMs, with owl monkey as a sister outgroup to the sister group of squirrel monkey and capuchin monkey

The Dfam community resource of transposable element families, sequence models, and genome annotations.

Dfam is an open access database of repetitive DNA families, sequence models, and genome annotations. The 3.0-3.3 releases of Dfam ( https://dfam.org ) represent an evolution from a proof-of-principle collection of transposable element families in model organisms into a community resource for a broad range of species, and for both curated and uncurated datasets. In addition, releases since Dfam 3.0 provide auxiliary consensus sequence models, transposable element protein alignments, and a formalized classification system to support the growing diversity of organisms represented in the resource. The latest release includes 266,740 new de novo generated transposable element families from 336 species contributed by the EBI. This expansion demonstrates the utility of many of Dfam\u27s new features and provides insight into the long term challenges ahead for improving de novo generated transposable element datasets

Sequence analysis and characterization of active human alu subfamilies based on the 1000 genomes pilot project

© The Author(s) 2015. The goal of the 1000 Genomes Consortium is to characterize human genome structural variation (SV), including forms of copy number variations such as deletions, duplications, and insertions. Mobile element insertions, particularly Alu elements, are major contributors to genomic SV among humans. During the pilot phase of the project we experimentally validated 645 (611 intergenic and 34 exon targeted) polymorphic young Alu insertion events, absent fromthe human reference genome. Here, we report high resolution sequencing of 343 (322 unique) recent Alu insertion events, along with their respective target site duplications, precise genomic breakpoint coordinates, subfamily assignment, percent divergence, and estimated A-rich tail lengths.All the sequenced Alu lociwerederived from the Alu Y lineagewith no evidence of retrotransposition activity involving older Alu families (e.g., AluJandAluS). AluYa5 is currently themost active Alu subfamily in the human lineage, followed by AluYb8, andmany others including three newly identified subfamilieswe have termed AluYb7a3, AluYb8b1, and AluYa4a1. This report provides the structural details of 322 unique Alu variants from individual human genomes collectively adding about 100 kb of genomic variation. Many Alu subfamilies are currently active in human populations, including a surprising level of AluY retrotransposition. Human Alu subfamilies exhibit continuous evolution with potential drivers sprouting new Alu lineages

Amplification dynamics of platy-1 retrotransposons in the cebidae platyrrhine lineage

© 2019 The Author(s). Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. Platy-1 elements are Platyrrhine-specific, short interspersed elements originally discovered in the Callithrix jacchus (common marmoset) genome. To date,only themarmoset genomehas been analyzed for Platy-1 repeat content.Here,we report full-length Platy-1 insertions in other NewWorld monkey (NWM) genomes (Saimiri boliviensis, squirrel monkey; Cebus imitator, capuchin monkey; and Aotus nancymaae, owl monkey) and analyze the amplification dynamics of lineage-specific Platy-1 insertions. A relatively small number of full-length and lineage-specific Platy-1 elements were found in the squirrel, capuchin, and owl monkey genomes compared with the marmoset genome. In addition, only a few older Platy-1 subfamilies were recovered in this study, with no Platy-1 subfamilies younger than Platy-1-6. By contrast, 62 Platy-1 subfamilieswere discovered in themarmoset genome.All of the lineagespecific insertions found in the squirrel and capuchin monkeys were fixed present. However, 15%of the lineage-specific Platy-1 loci in Aotus were polymorphic for insertion presence/absence. In addition, two new Platy-1 subfamilies were identified in the owl monkey genome with low nucleotide divergences compared with their respective consensus sequences, suggesting minimal ongoing retrotransposition in the Aotus genus and no current activity in the Saimiri, Cebus, and Sapajus genera. These comparative analyses highlight the finding that the high number of Platy-1 elements discovered in themarmoset genome is an exception among NWManalyzed thus far, rather than the rule. Future studies are needed to expand upon our knowledge of Platy-1 amplification in other NWM genomes

Alu insertion polymorphisms shared by Papio baboons and Theropithecus gelada reveal an intertwined common ancestry

© 2019 The Author(s). Background: Baboons (genus Papio) and geladas (Theropithecus gelada) are now generally recognized as close phylogenetic relatives, though morphologically quite distinct and generally classified in separate genera. Primate specific Alu retrotransposons are well-established genomic markers for the study of phylogenetic and population genetic relationships. We previously reported a computational reconstruction of Papio phylogeny using large-scale whole genome sequence (WGS) analysis of Alu insertion polymorphisms. Recently, high coverage WGS was generated for Theropithecus gelada. The objective of this study was to apply the high-Throughput poly-Detect method to computationally determine the number of Alu insertion polymorphisms shared by T. gelada and Papio, and vice versa, by each individual Papio species and T. gelada. Secondly, we performed locus-specific polymerase chain reaction (PCR) assays on a diverse DNA panel to complement the computational data. Results: We identified 27,700 Alu insertions from T. gelada WGS that were also present among six Papio species, with nearly half (12,956) remaining unfixed among 12 Papio individuals. Similarly, each of the six Papio species had species-indicative Alu insertions that were also present in T. gelada. In general, P. kindae shared more insertion polymorphisms with T. gelada than did any of the other five Papio species. PCR-based genotype data provided additional support for the computational findings. Conclusions: Our discovery that several thousand Alu insertion polymorphisms are shared by T. gelada and Papio baboons suggests a much more permeable reproductive barrier between the two genera then previously suspected. Their intertwined evolution likely involves a long history of admixture, gene flow and incomplete lineage sorting

A high-quality bonobo genome refines the analysis of hominid evolution

The divergence of chimpanzee and bonobo provides one of the few examples of recent hominid speciation1,2. Here we describe a fully annotated, high-quality bonobo genome assembly, which was constructed without guidance from reference genomes by applying a multiplatform genomics approach. We generate a bonobo genome assembly in which more than 98% of genes are completely annotated and 99% of the gaps are closed, including the resolution of about half of the segmental duplications and almost all of the full-length mobile elements. We compare the bonobo genome to those of other great apes1,3,4,5 and identify more than 5,569 fixed structural variants that specifically distinguish the bonobo and chimpanzee lineages. We focus on genes that have been lost, changed in structure or expanded in the last few million years of bonobo evolution. We produce a high-resolution map of incomplete lineage sorting and estimate that around 5.1% of the human genome is genetically closer to chimpanzee or bonobo and that more than 36.5% of the genome shows incomplete lineage sorting if we consider a deeper phylogeny including gorilla and orangutan. We also show that 26% of the segments of incomplete lineage sorting between human and chimpanzee or human and bonobo are non-randomly distributed and that genes within these clustered segments show significant excess of amino acid replacement compared to the rest of the genome

Methodologies for the De novo Discovery of Transposable Element Families

The discovery and characterization of transposable element (TE) families are crucial tasks in the process of genome annotation. Careful curation of TE libraries for each organism is necessary as each has been exposed to a unique and often complex set of TE families. De novo methods have been developed; however, a fully automated and accurate approach to the development of complete libraries remains elusive. In this review, we cover established methods and recent developments in de novo TE analysis. We also present various methodologies used to assess these tools and discuss opportunities for further advancement of the field

DOES THE AMOUNT OF SOCIAL OR OBJECT PLAY BETWEEN INFANT AND MOTHER RELATE TO INFANT CONSTRUCTION ABILITY?

Infants prefer to watch caregivers during object play, as opposed to face-to-face play or watching objects alone (Deak et al., 2014). Infants spend more time looking at a caregiver\u27s hands and objects during manipulation, as opposed to the caregiver\u27s face (Yu & Smith, 2013). Parents who engage in object play more may be encouraging their infants to manipulate objects more skillfully, than parents who only engage socially. Object construction is one way that infants begin to show an increased ability to manipulate objects (Marcinowski et al., 2016). Thus, infants whose parents encourage object play are expected to perform more object constructions, than infants whose parents engage more socially. The purpose of the study is to investigate whether parent object or social play correlates with infant construction ability. Parent-infant dyads (n=31) were tested for dyadic play at the emergence of object construction ability. Parents were provided with four toys, and instructed to spend five minutes interacting with their infant. Reliable coders marked the duration of object and social play. Object play was defined as dyadic interactions in which a toy was involved, while social play was defined as interactions without the use of toys. For the object construction task, each infant was separately given six sets of toys that could be combined in some manner. A successful construction was defined as occurring when an object was successfully built upon a base item. Correlational analyses are expected to reveal a negative correlation, such that increases in social play will be correlated with decreases in construction ability. A positive correlation between object play and construction ability is expected. Increases in object play are expected to be correlated with increases in construction ability. Previous research supports the idea that infants observe object manipulations of their caregiver(s) by watching the caregiver\u27s hands and objects when engaged in object manipulation. However, there is no research investigating the impact of these observations on infant behavioral outcomes. We propose that object play, as opposed to social play, has an important role on an infant\u27s subsequent ability to create structures from objects successfully

Curation Guidelines for de novo Generated Transposable Element Families.

Transposable elements (TEs) have the ability to alter individual genomic landscapes and shape the course of evolution for species in which they reside. Such profound changes can be understood by studying the biology of the organism and the interplay of the TEs it hosts. Characterizing and curating TEs across a wide range of species is a fundamental first step in this endeavor. This protocol employs techniques honed while developing TE libraries for a wide range of organisms and specifically addresses: (1) the extension of truncated de novo results into full-length TE families; (2) the iterative refinement of TE multiple sequence alignments; and (3) the use of alignment visualization to assess model completeness and subfamily structure. © 2021 Wiley Periodicals LLC. Basic Protocol: Extension and edge polishing of consensi and seed alignments derived from de novo repeat finders Support Protocol: Generating seed alignments using a library of consensi and a genome assembly