Taxacom: RES: Barcodes and species

Tue May 28 09:01:24 CDT 2024

Well as another example the genus Chelodina in turtles. Chelodina expansa
for example has no known mitochondria of it's own, having that of C.
longicollis or C. canni I depending on locality and sympatry. These species
are in different subgenera as an aside. C. canni and C. longicollis
hybridize in one river at an overlap zone but no where else, they have
hybrid vigor. C. rugosa has hybrids with both C. burrungandjii and C.
canni, including 3 way hybrids (is F1 hybrids breed with a 3rd species).
All these are wild hybrids by the way. Further extremes are the C. parkeri
x Emydura subglobosa hybrid (snake neck x short neck) also can be found in
wild. Basically seems in turtles hybrids are normal, at least within family
level, cross genus is common, as is cross species. I cannot think of any
cross family hybrids found yet.

Several described species of turtles have turned out to be wild hybrids and
sunk, eg Mauremys iversoni which was a cross genus hybrid.

I suspect it may be a survival strategy in turtles and may explain their
230 million year existence. Or hybrids are far more common than suspected
or assumed.

I would not assume this is rare at all.

Cheers Scott

On Sun, May 19, 2024, 8:58 AM Lücking, Robert via Taxacom <
taxacom at lists.ku.edu> wrote:

> Dear Paolo and John,
>
> I do not think complex evolutionary theory is necessary here. I am not
> sure how well insect barcodes resolve species complexes, but in Fungi, the
> default ITS barcoding marker may in some cases not be resolved enough. I.e.
> two different, closely related species may have identical barcodes simply
> because they evolved faster that the barcode. In some fungi this has been
> shown comparing ITS barcodes with highly resolving approaches, e.g.
> microsatellites or RADseq, where the distinct lineages become apparent. In
> other cases, a secondary barcode has been introduced which is more highly
> resolving than ITS.
>
> There are some reported cases where hybridization/introgression may have
> led to shared barcodes between not necessarily closely related species.
>
> Regards
> Robert
>
>
> -----Ursprüngliche Nachricht-----
> Von: Taxacom <taxacom-bounces at lists.ku.edu> Im Auftrag von Paulo Buckup
> via Taxacom
> Gesendet: Sonntag, 19. Mai 2024 12:58
> An: 'John Grehan' <calabar.john at gmail.com>; 'taxacom' <
> taxacom at mailman.nhm.ku.edu>
> Betreff: Taxacom: RES: Barcodes and species
>
> Hi John,
>         The sharing of the same mitochondrion by different species is
> theoretically possible under the following conditions:
>         1. Hybridization has occurred involving a female of species A and
> a male od species B, and a hybrid female descendant is fertile and mates
> with other members of species B, successfully spreading its mitochondria
> among members of species B.
>         2. The spread of mitochondria from the original hybrid into the
> entire population of species B occurs very fast, before the mitochondrion
> accumulates new mutations.
>         The difficulty resides in Step 2. Unless descendants of the hybrid
> genotype have a tremendous reproductive advantage, it is unlikely that
> mitochondrion A will completely replace mitochondrion B fast enough in
> species B. In principle, evolution of barcodes is mostly random, and there
> is little selective advantages in (mostly) synonymous third-base codons.
>             The alternative, fast speciation with delayed mitochondrial
> differentiation, is even more unlikely, because nuclear genes (those that
> produce distinct genitalia and white spots) evolve a lot more slowly than
> the mitochondrial barcodes.
>              Before invoking horizontal transfer of mitochondria, lab
> mislabeling and lab contamination must be ruled out. Sometimes minute
> contamination is present in lab reagents, but only becomes visible is there
> is a species-specific failure of primers - so check for this insidious
> problem.
>
> Cheers,
>
> Paulo Buckup
> ---
> Paulo A. Buckup, Ph.D.         https://nam10.safelinks.protection.outlook.com/?url=http%3A%2F%2Flattes.cnpq.br%2F7200068520418368&data=05%7C02%7Ctaxacom%40lists.ku.edu%7Cdda8c44cfeee47d1613208dc7f1eb2b2%7C3c176536afe643f5b96636feabbe3c1a%7C0%7C0%7C638525017762681583%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C60000%7C%7C%7C&sdata=9gKyCb%2F39fV3077RJOkE5G098gQK%2BWJAacrT1xY1ryw%3D&reserved=0
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> -----Mensagem original-----
> De: Taxacom [mailto:taxacom-bounces at lists.ku.edu] Em nome de John Grehan
> via Taxacom Enviada em: domingo, 19 de maio de 2024 03:07
> Para: taxacom <taxacom at mailman.nhm.ku.edu>
> Assunto: Taxacom: Barcodes and species
>
> As I am pretty ignorant of technical details of species designation and
> barcode identity, I would be grateful for any feedback on whether it is
> possible for two 'species' to have identical 'barcodes' (never liked that
> label with its essentialist connotations).
>
> I have a colleague who has collected some ghost moths from the same date
> and location. There are two morphs - for simplicity 'white spot' and
> 'plain'.
> Dissections of genitalia also show differences, with the white spot and
> plain each showing consistent differences, although only 2 specimens for
> white spot and 3 for plain. Even with this small sample I am kind of
> intrigued that the external difference matches the internal difference.
>
> The genitalic differences are prominent enough that I would normally view
> them as indicative of species difference. Perhaps there is a single
> polymorphic species, but correlated external and internal differences were
> a bit of a surprise. Any comments or enlightenment would be very welcome.
>
> Cheers, John
>
> --
> https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Fhepialidsoftheworld.com.au%2F&data=05%7C02%7Ctaxacom%40lists.ku.edu%7Cdda8c44cfeee47d1613208dc7f1eb2b2%7C3c176536afe643f5b96636feabbe3c1a%7C0%7C0%7C638525017762837886%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C60000%7C%7C%7C&sdata=s%2Bk6Z9b1%2BYqfmiiMrBrOPY0TJpClQ5%2BCUe5VzmEm8IQ%3D&reserved=0 (use the 'visit archived web site'
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