A total of 293 Darwin’s finch samples representing 18 species, 4 hybrids and 2 outgroup species (Loxigilla noctis and Tiaris bicolor) from 16 islands6,9,10,11 were included in the study. Island names are indicated above finch species, hybrids and their respective sampling sizes. Finch species abbreviations: Big Bird lineage (Geospiza fortis x Geospiza conirostris), C. fus (Certhidea fusca), C. hel (Camarhynchus heliobates), C. pal (Camarhynchus pallidus), C. par (Camarhynchus parvulus), C. pau (Camarhynchus pauper), C. psi (Camarhynchus psittacula), C. oli (Certhidea olivacea), G. acu (Geospiza acutirostris), G. con (Geospiza conirostris), G. dif (Geospiza difficilis), G. for (Geospiza fortis), G. ful (Geospiza fuliginosa), G. mag (Geospiza magnirostris), G. pro (Geospiza propinqua), G. sca (Geospiza scandens), G. sep (Geospiza septentrionalis), Hybrid ff (Hybrid G. fortis x G. fuliginosa), Hybrid ffs (Hybrid G. fortis x G. fuliginosa x G. scandens), Hybrid fs (Hybrid G. fuliginosa x G. scandens), L. noc (Loxigilla noctis), T. bic (Tiaris bicolor), P. cra (Platyspiza crassirostris), P. ino (Pinaroloxias inornata).
It's an account of how Darwin's finches were used as the basis for showing how the Theory of Evolution can explain the presence and differences in the remnants of ancient retroviruses in the genome of those finches that inspired Charles Darwin to formulate the Theory of Evolution all those years ago.
Briefly, retroviruses are a class of RNA virus that are able to build a DNA template from their RNA and insert it into their hosts genome where it becomes almost impossible for the immune system to recognise it as an intruder. Over time these retroviruses can mutate and cease to function as viruses, so they become an inherited part of the species genome as 'endogenous retroviruses' (ERVs). Mostly they simply add to the species junk DNA but sometimes they can be exapted for a novel use or can be a cause of cancers and neurodegenerative conditions. Some ERVs became incorporated into early vertebrates many millions of years ago and have been passed down through the generations, slowly mutating as they do so, and into the daughter taxons of these stem species. So they form one of the best pieces of evidence of evolution in that a family tree of these ERV fragments can be reconstructed to form a family tree of the resulting taxons.
This no less true for Darwin's Finches and so act as confirmation of Darwin's basic explanation for the similarities and differences between the Galapagos finches on the different islands. Darwin, of course, knew nothing of DNA or ERVs so it must be galling for Creationists to have his basic idea confirmed so conclusively using a strand of evidence of which he was completely unaware. However, the researchers found that the pattern of radiation and divergence was complicated by frequent cross breeding between partially diverged species (something also predictable from the TOE).
The research was conducted by scientists from Uppsala University, Upsala, Sweden and Princeton University, Princeton, NJ, USA and is published, open access, in Nature Communications. In the Upsala University news release, the scientists explain their research and its significance:
Vertebrate genomes are repositories for retrovirus code that was deposited into germ line as inherited endogenous retroviruses during evolution. Researchers from Uppsala University and Princeton University now provide new findings about retroviral establishment and distribution among Darwin’s finches. The findings are being published in Nature Communications.
The unexpected ERV variation suggests recent retrovirus infection and historical changes in gene flow and selection.
Jason Hill, co-first author
Science for Life Laboratory
Department of Medical Biochemistry and Microbiology
Uppsala University, Upsala, Sweden.The ERV distribution along and between chromosomes, and across the finch species, suggests connection between ERVs and the rapid speciation.
Mette Lillie, co-first author
Science for Life Laboratory
Department of Medical Biochemistry and Microbiology
Uppsala University, Upsala, Sweden.The researchers examined whole genomes sampled from the entire Darwin’s finch radiation and found shared endogenous retroviruses (ERV) among all individual birds suggesting that most retrovirus-host interactions pre-date host speciation. They also found considerable ERV variation across different populations of Darwin’s finches suggesting more recent retrovirus colonization of germ line. Natural selection can then lead to enrichment or loss of ERVs. Occurrence is also affected by crosses between finch species, which results in gene flow including the ERVs.Darwin’s finches provide a wonderful resource for connecting ERV variation across host populations with host genes and phenotypes, for identifying historic virus-host interactions and potential contributions to host biology
Patric Jern, Senior author
Science for Life Laboratory
Department of Medical Biochemistry and Microbiology
Uppsala University, Upsala, Sweden.
By mapping ERV variation across all species of Darwin’s finches and comparing with related finch species, the researchers highlight geographical and historical patterns of retrovirus-host occurrence.
As a well examined species group which has become synonymous with evolution studies, Darwin’s finches represent a natural model for evaluating the extent and timing of retroviral activity in hosts undergoing speciation and colonization of new environments.
In their abstract to their publishe paper, the authors give more technicl detail:
AbstractIt should only be a matter of time before the Creationist cult leaders have worked out a response to this news and found something to fool their credulous dupes with by way of a reason to dismiss it. It will almost certainly involve rubbishing the science and/or the scientists, but what it won't address is the fact that these ERV's can be arranged into nested hierarchies that map so neatly onto other hierarchies such a mitochondrial DNA and, in this case, other evidence of an evolutionary radiation from a founder population several million years ago.
Endogenous retroviruses (ERVs) are inherited remnants of retroviruses that colonized host germline over millions of years, providing a sampling of retroviral diversity across time. Here, we utilize the strength of Darwin’s finches, a system synonymous with evolutionary studies, for investigating ERV history, revealing recent retrovirus-host interactions in natural populations. By mapping ERV variation across all species of Darwin’s finches and comparing with outgroup species, we highlight geographical and historical patterns of retrovirus-host occurrence, utilizing the system for evaluating the extent and timing of retroviral activity in hosts undergoing adaptive radiation and colonization of new environments. We find shared ERVs among all samples indicating retrovirus-host associations pre-dating host speciation, as well as considerable ERV variation across populations of the entire Darwin’s finches’ radiation. Unexpected ERV variation in finch species on different islands suggests historical changes in gene flow and selection. Non-random distribution of ERVs along and between chromosomes, and across finch species, suggests association between ERV accumulation and the rapid speciation of Darwin’s finches.
Hill J., Lillie M., Pettersson M.E., Rubin C-J., Grant B.R., Grant P.R., Andersson L. and Jern P. (2022)
Spatiotemporal variations in retrovirus-host interactions among Darwin’s finches.
Nature Commun.; 13, 6033. DOI: 10.1038/s41467-022-33723-w
Copyright: © 2022 The authors.
Published by Springer Nature Ltd. Open access
Reprinted under a Creative Commons Attribution 4.0 International license (CC BY 4.0)
And of course, the research would not have been conducted in that way had the scientists had the slightest doubt about the truth of the TOE as the best explanation for biodiversity and the similarity and difference between species and related taxons. Far from being a theory in crisis as Creationist frauds are still telling their willing dupes, but every day science shows the childish notion of magic creation to be a notion which is easily refuted, and which should play no part in any scientific explanation of natural phenomena. The only reason Creationists can't understand that is because Creationists don't understand the science and can't afford to allow themselves to gain the necessary understanding for fear of discovering that they are wrong.
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