scholarly journals Sex Chromosome Evolution in Amniotes: Applications for Bacterial Artificial Chromosome Libraries

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Daniel E. Janes ◽  
Nicole Valenzuela ◽  
Tariq Ezaz ◽  
Chris Amemiya ◽  
Scott V. Edwards
Keyword(s):  
Bacterial Artificial Chromosome ◽  
Chromosome Evolution ◽  
Common Ancestor ◽  
Sex Chromosome ◽  
Artificial Chromosome ◽  
Sex Chromosome Evolution ◽  
Target Species ◽  
Bac Clones ◽  
Bac Libraries ◽  
Experimental Approaches

Variability among sex chromosome pairs in amniotes denotes a dynamic history. Since amniotes diverged from a common ancestor, their sex chromosome pairs and, more broadly, sex-determining mechanisms have changed reversibly and frequently. These changes have been studied and characterized through the use of many tools and experimental approaches but perhaps most effectively through applications for bacterial artificial chromosome (BAC) libraries. Individual BAC clones carry 100–200 kb of sequence from one individual of a target species that can be isolated by screening, mapped onto karyotypes, and sequenced. With these techniques, researchers have identified differences and similarities in sex chromosome content and organization across amniotes and have addressed hypotheses regarding the frequency and direction of past changes. Here, we review studies of sex chromosome evolution in amniotes and the ways in which the field of research has been affected by the advent of BAC libraries.

scholarly journals Dynamic Patterns of Sex Chromosome Evolution in Neognath Birds: Many Independent Barriers to Recombination at the ATP5F1A Locus

2021 ◽  
Author(s):  
Rebecca T. Kimball ◽  
Edward L. Braun
Keyword(s):  
Sex Chromosomes ◽  
Substitution Rate ◽  
Chromosome Evolution ◽  
Common Ancestor ◽  
Sex Chromosome ◽  
Purifying Selection ◽  
W Chromosome ◽  
Sex Chromosome Evolution ◽  
Dynamic Nature ◽  
Genome Assemblies

Avian sex chromosomes evolved after the divergence birds and crocodilians from their common ancestor, so they are much younger than the better-studied chromosomes of mammals. It has long been recognized that there may have been several stages to the evolution of avian sex chromosomes. For example, the CHD1 undergoes recombination in paleognaths but not neognaths. Genome assemblies have suggested there may be variation in the timing of barriers to recombination among Neognathae, but there remains little understanding of the extent of this variability. Here, we look at partial sequences of ATP5F1A, which is on the avian Z and W chromosomes. It is known that recombination of this gene has independently ceased in Galliformes, Anseriformes, and at least five neoavian orders, but whether there are other independent cessations of recombination among Neoaves is not understood. We used a combination of data extracted from published chromosomal-level genomes with data collected using PCR and cloning to identify Z and W copies in 22 orders. Our results suggest there may be at least 19 independent cessations of recombination within Neognathae, and 3 clades that may still be undergoing recombination (or have only recently ceased recombination). Analyses of ATP5F1A protein sequences revealed an increased amino acid substitution rate for W chromosome gametologs, suggesting relaxed purifying selection on the W chromosome. Supporting this hypothesis, we found that the increased substitution rate was particularly pronounced for buried residues, which are expected to be more strongly constrained by purifying selection. This highlights the dynamic nature of avian sex chromosomes, and that this level of variation among clades means they should be a good system to understand sex chromosome evolution.

Construction and characterization of bacterial artificial chromosome library of black-handed spider monkey (Ateles geoffroyi)

Genome ◽  
2004 ◽  
Vol 47 (2) ◽  
pp. 239-245 ◽  
Author(s):  
Yaping Qian ◽  
Li Jin ◽  
Bing Su
Keyword(s):  
Bacterial Artificial Chromosome ◽  
Large Scale ◽  
Bac Library ◽  
Artificial Chromosome ◽  
Spider Monkey ◽  
Ateles Geoffroyi ◽  
Comparative Genomic ◽  
Average Insert Size ◽  
Bac Clones ◽  
Genomic Study

The large-insert genomic DNA library is a critical resource for genome-wide genetic dissection of target species. We constructed a high-redundancy bacterial artificial chromosome (BAC) library of a New World monkey species, the black-handed spider monkey (Ateles geoffroyi). A total of 193 152 BAC clones were generated in this library. The average insert size of the BAC clones was estimated to be 184.6 kb with the small inserts (50-100 kb) accounting for less than 3% and the non-recombinant clones only 1.2%. Assuming a similar genome size with humans, the spider monkey BAC library has about 11× genome coverage. In addition, by end sequencing of randomly selected BAC clones, we generated 367 sequence tags for the library. When blasted against human genome, they showed a good correlation between the number of hit clones and the size of the chromosomes, an indication of unbiased chromosomal distribution of the library. This black-handed spider monkey BAC library would serve as a valuable resource in comparative genomic study and large-scale genome sequencing of nonhuman primates.Key words: black-handed spider monkeys, Ateles geoffroyi, BAC library.

scholarly journals Sex and the flower – developmental aspects of sex chromosome evolution

2018 ◽  
Vol 122 (7) ◽  
pp. 1085-1101 ◽  
Author(s):  
Roman Hobza ◽  
Vojtech Hudzieczek ◽  
Zdenek Kubat ◽  
Radim Cegan ◽  
Boris Vyskot ◽  
...  
Keyword(s):  
Chromosome Evolution ◽  
Sex Chromosome ◽  
Sex Chromosome Evolution
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