Taxacom: RES: Barcodes and species

Sun May 19 06:57:36 CDT 2024

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%7C8467716d188d4e7bff2808dc77fae4ad%7C3c176536afe643f5b96636feabbe3c1a%7C0%7C0%7C638517167118799172%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C40000%7C%7C%7C&sdata=%2F%2FthQT1zRhgbssIlERF%2BY3JMCiYHrYGtk3gc8sZiCiM%3D&reserved=0
Dept. de Vertebrados
https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Fscholar.google.com%2Fcitations%3Fuser%3Dybi4V0kAAAAJ&data=05%7C02%7Ctaxacom%40lists.ku.edu%7C8467716d188d4e7bff2808dc77fae4ad%7C3c176536afe643f5b96636feabbe3c1a%7C0%7C0%7C638517167118799172%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C40000%7C%7C%7C&sdata=ZXm5sKJuEFpUdj9J0j9s%2FtdwiZopRWH4Po%2Fn%2FO3Fozs%3D&reserved=0
Museu Nacional / UFRJ        e-mail: buckup at acd.ufrj.br Quinta da Boa Vista             tel.:+55(21)99994-0223
20940-040 Rio de Janeiro, RJ   Brasil
-----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%7C8467716d188d4e7bff2808dc77fae4ad%7C3c176536afe643f5b96636feabbe3c1a%7C0%7C0%7C638517167118799172%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C40000%7C%7C%7C&sdata=X2mB3VS3wuhGtHtfSBwAksIYw6R2hichXocijGct%2FME%3D&reserved=0 (use the 'visit archived web site'
link, then the 'Ghost Moth Research page' link.
_______________________________________________
Taxacom Mailing List

Send Taxacom mailing list submissions to: taxacom at lists.ku.edu For list information; to subscribe or unsubscribe, visit:
https://lists.ku.edu/listinfo/taxacom
You can reach the person managing the list at: taxacom-owner at lists.ku.edu

Nurturing nuance while assailing ambiguity for about 37 years, 1987-2024.

_______________________________________________
Taxacom Mailing List

Send Taxacom mailing list submissions to: taxacom at lists.ku.edu For list information; to subscribe or unsubscribe, visit: https://lists.ku.edu/listinfo/taxacom
You can reach the person managing the list at: taxacom-owner at lists.ku.edu

Nurturing nuance while assailing ambiguity for about 37 years, 1987-2024.