RESUMEN
Falcons are diverse birds of cultural and economic importance. They have undergone major lineage-specific chromosomal rearrangements, resulting in greatly-reduced chromosome counts relative to other birds. Here, we use 10X Genomics linked reads to provide new high-contiguity genomes for two gyrfalcons, a saker falcon, a lanner falcon, three subspecies of peregrine falcons, and the common kestrel. Assisted by a transcriptome sequenced from 22 gyrfalcon tissues, we annotate these genomes for a variety of genomic features, estimate historical demography, and then investigate genomic equilibrium in the context of falcon-specific chromosomal rearrangements. We find that falcon genomes are not in AT-GC equilibrium with a bias in substitutions towards higher AT content; this bias is predominantly but not exclusively driven by hypermutability of CpG sites. Small indels and large structural variants were also biased towards insertions rather than deletions. Patterns of disequilibrium were linked to chromosomal rearrangements: falcons have lost GC content in regions that have fused to larger chromosomes from microchromosomes and gained GC content in regions of macrochromosomes that have translocated to microchromosomes. Inserted bases have accumulated on regions ancestrally belonging to microchromosomes, consistent with insertion-biased gene conversion. We also find an excess of interspersed repeats on regions of microchromosomes that have fused to macrochromosomes. Our results reveal that falcon genomes are in a state of flux. They further suggest that many of the key differences between microchromosomes and macrochromosomes are driven by differences in chromosome size, and indicate a clear role for recombination and biased-gene-conversion in determining genomic equilibrium.
RESUMEN
A total of 3975 fecal samples, originated from the same number of individual birds, from 7 dedicated falcon hospitals, were examined to determine the prevalence of Caryospora species in the falcon population used in the sport of falconry in the United Arab Emirates (UAE). From that total, 297 (7.5%) were positive for the presence of Caryospora species. The falcons were all captive bred within the UAE and abroad, mainly from Germany, Spain, the United States, and Canada. Positive samples for the presence of Caryospora species were sporulated, and the taxonomy was established based on morphologic characteristics. The results showed the prevalence of the following Caryospora species: C kutzeri 41.4%, C neofalconis 25.6%, C megafalconis 18.2%, C falconis 10.4%, C cherrughi 3.7%, and C boeri 0.7%. The prevalence of Caryospora species among the various falcon species in this study was: gyr × peregrine hybrid falcons ( Falco rusticolus × Falco peregrinus), 27.3%; gyr falcons ( Falco rusticolus), 25.6%; peregrine falcons ( Falco peregrinus), 20.5%; saker falcons ( Falco cherrug), 16.5%; gyr × saker hybrid falcons ( Falco rusticolus × Falco cherrug), 8.1%; Eurasian kestrels ( Falco tinnunculus), 1%; red-napped shaheen ( Falco pelegrinoides babylonicus), 0.7%; and American kestrels ( Falco sparverius), 0.3%.
