Talk:Hybrid (biology)

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[edit] comment

This may have been mentioned previously, I'm not sure. The plant section of this article is confusing two distinctly different types of hybrids. An interspecific hybrid is the hybridization of two distinct taxa, usually refering to two seperate species within a genus. Most cultivars are called hybrids, however this refers to F1 hybrids. The technical definition of an F1 hybrid as far as I know is the cross between two inbred lines within a single sepcies of plant. This is where the term heterosis is used, where the resulting F1 hybrid is more vigorous than either of the parental lines.

The cross between two cultivars would not, in my opinion, be considered a hybrid, however I guess that this could be argues. However, if it were a hybrid it would be an intra-specific hybrid as it is a cross within the same species. In this case there would be little or no hybrid vigour.

Heterosis does not occur in animals because there is no way for an animal so self "pollinate", thus there is no way to create a true inbred line. Heterosis only occurs in intra-specific hybridizations of IBLs (in-bred lines).

This article does not differentiate between the two distinct uses of the term hybrid in plants, thus it makes some innacurate claims.

Cultivars might be hybrids or they might not be in plants, this depends on the group of plants. Your using a to specific definition for F1 hybrids, F1 hybrids are just the first generation of any hybrid mating,and are just the result of the crossing of two different groups of genetically different indavigauls and the term is used in animals too, most people learn about genetics in high school were fruit flies are used and you make crosses that are labeled F1, F2, ect. Not all hybrids, as you are using the term, exhibit hybrid vigor- there is also hybrid suppression and most often hybrids, as you are using the term, are weaker than the parents. The definition of hybrid is simple, and is just the mixing of two differently gene pools. They don't have to be heterozygous or homozygous groups or even that different from each other. Hardyplants 22:30, 10 August 2007 (UTC)

-> When I was taking plant breeding, we were told that true F1 hybrids were the result of crossing two inbred lines. It is possible that this term is used less specifically by people in other areas or even other groups of plant breeders, but this is what we were taught and it is what I generally use. The crosses of fruit flies are termed F1, F2 etc., but that does not make them hybrids IMO, simply the F1, F2, etc. generation. Just as the first generation of any cross is termed the F1 generation, I do not consider them hybrids unless the parental lines were very distict. However, it is possible that my definition is more specific than it needs to be for general use.

The technical definition of an F1 hybrid as far as I know is the cross between two inbred lines within a single sepcies of plant.

No this is to narrow of an application of the term hydrid, the first generation is a TYPE of F1 hybrid just as trucks are a type of vehicles.


The cross between two cultivars would not, in my opinion, be considered a hybrid, however I guess that this could be argued. However, if it were a hybrid it would be an intra-specific hybrid as it is a cross within the same species.

Your mixing a lot of different levels of definitions together; cultivars might be any thing genetically from "pure" species to highly complex mixes of many species. Intra-specific hybrids would be hard to claim for crosses between most Hosta and daylily cultivars plus many more cultivated plant groups since they are the result of crosses between a number of different species and of coarse these crosses have not settled out yet into species them selves. Hardyplants 22:50, 10 August 2007 (UTC)

->The term cultivar is an abbreviation for a "cultivated variety". A variety is below the sub-species level, thus a cultivar can not be a "highly complex mix of many species". Daylillies are typically clonally propagated correct? If so, they are not true cultivars, although they would commonly be referred to as such. To technically be a cultivar it must be a cultivated breeding population that exhibit characteristics that allow them to be distinguished from the other members of that species.

This is incorrect. A cultivar is named according to the International Code of Nomenclature for Cultivated Plants, and bears no direct relationship to the varietas of the International Code of Botanical Nomenclature.--Curtis Clark 01:41, 15 August 2007 (UTC)

-> Any hybrid within a species is an intra-specific hybrid. IMO the cross between two daylilly cultivars would not be a hybrid at all unless they were, as I mentioned before, inbred lines or at least genetically distinct. However, it could be considered an FX (whatever generation it is) interspecific hybrid of the original species if you do not consider them as species in their own right.

[edit] Question

I am not sure how to work these two different definitions into the same article. Should it be separated into two articles. Where should go the discussion of hybrid vigor, the Green Revolution, F1 hybrids, F2 hybrids, diploid, triploid, tetraploid, etc.? Rmhermen 14:44, Nov 14, 2003 (UTC)

[edit] Comment 2

I have to agree with Rmhermen... Leave me a message on my talk-page if you have any questions or concerns with this comment Yashtulsyan 19:27, 29 December 2006 (UTC)

[edit] Comment 3

There is another issue: a hybrid is a cross between two specimen belonging to taxons below the genera level. (This includes crosses with subspecies varieties subvarieties and forms).

There is a second issue: a hybrid of two cultivars. Actually a cultivar is most often a hybrid in its own right. The way cultivars are reproduced is most often under controlled conditions and they can be clones. GerardM

In botany it is accepted to talk about taxons lower than subspecies. So when you have natural varieties, and cross them you get hybrids. This does explain to me why a hybrid can be stronger in botany and not in zoology. Can anyone explain WHY the concept of variety or form is absent in zoology? GerardM

Wouldn't that be breed for domestic animals at least? Rmhermen 21:50, Dec 11, 2003 (UTC)
A breed is indeed domestic. As such they are not taxonomically relevant. You do not find a "fresian holstein" for a cow or an "arabian thoroughbred" for a horse when studying the taxonomy of animals. GerardM

[edit] Question for the biologists:

Is this line from the 4th paragraph true, strictly speaking? 'To create specialised plants is called cross-fertilisation.' Is that actually the definition of 'cross-fertilisation'?

English is not my primary language but to me this fourth paragraph is wrong. GerardM 22:01, 23 Jul 2004 (UTC)

Can't you cross-fertilize for another reason? And wouldn't grafting, e.g., be another way of creating a specialized plant? Quill 22:01, 19 Jul 2004 (UTC)

A graft is special but it is not one organism they are two. The rootstock has properties that make for a more vibrant growth of the graft. A hybrid is one organism. GerardM 21:59, 23 Jul 2004 (UTC)
Cross-fertilization isn't really the correct term to use here, the sentence as it stands does not convery any information so I'm deleting it and adding a link to plant breeding where hybrids are discussed.--nixie 02:20, 1 Mar 2005 (UTC)

I don't think they should merge, because having two articles allows for more specified results... If you were looking for specific hybrids... I think parts of the "Hybrid" article sould assimilate to the other article.

When refering to plants cross pollination is probably a better term; cross fertilisation can also refer to the artificial fertilisation in animals. The generalised hybrid article makes this clearer but perhaps links to plant propagation would be appropriate?

[edit] Cypresses

Whilst the example of the cypresses is not untrue, it's not actually very pointful. Plants will readily hybridize with other plants of the same genus. All the other examples are animals, hybrids of which are much more unusual. I'm not sure the single plant example belongs here.

[edit] 66.42.123.130's edits

I'm not sure if this anon user's addition should even be kept on this page, but I thought I would at least format it correctly for the time being. [[User:Lachatdelarue|Lachatdelarue (talk)]] 12:53, 19 Sep 2004 (UTC)

It's a good question, Lach. I like the entry, but since this article is about biology (in the real world), perhaps this is misplaced. So where to put it? Another article, with a link at hybrid (disambiguation)? Quill 23:24, 20 Sep 2004 (UTC)

[edit] Wolphin

In the article, it says that a wolphin is a cross between a whale and a dolphin, but that's actually not true. It is a cross between a False Killer Whale and a Bottlenose Dolphin, both of which are dolphins, as the article it links to points out.

[edit] Hybrid Fish

I think that hybrid fish should be added to the list such as the stripe bass (a.k.a. striper), which is a mix of a large mouth bass and a small mouth bass, unless a hybrid fish article is already made (which i can't find it if there is one). If you can find out about any hybrid fish information please add a new section called hybrid fish.- Biggal6 12:51, 8 November 2005 (EST)

[edit] What happens at the chromosome level in hybrid crosses?

This has just been added by User:Pschemp:

Continuous backcrossing to one of the species, in an effort to make the resulting animal more like one of the original species does not guarantee that successive generations will be "mostly" or even a given percentage of that species. This is due to the fact that during meiosis, fifty percent of the parent's genetic material is selected, but the part is selected at random. Thus a hybrid does not pass on exactly half of the genes of each of the parental species. While the average may tend to one species or the other, it is technically possible to end up with an animal that is still genetically fifty percent of each of the original species, even many generations removed from the original cross. Thus, even after extensive breeding, a hybrid is still a hybrid, and can never become one of the original species or the other.

What is sorely missing is an explanation of whether crossing over occurs at hybrid meiosis or not, and what happens to unpaired chromosomes (if parental species differ in karyotype). I understand that in normal meiosis, there is at least one crossing over per chromosome to ensure proper segregation.

As the passage stands, the conclusion does not follow from the premises. - Samsara contrib talk 00:31, 20 January 2006 (UTC)

I am countering the argument that since animal C (a hybrid of A and B)has been backcrossed X number of times to animal B, that it is now animal B. If you have a clearer way of explaining why this is not so, please help. (I'm trying to write this in a friendly manner for non-geneticists.) What I'm saying here is that in the cases where a fertile hybrid can be obtained (for example a wild and domestic cat cross where the F1 female is fertile), and then it is bred to a domestic, and the offspring bred to a domestic, etc...that you can't specify at any time down the line what ratio of domestic to wild cat is present due to random assortment of the chromosomes in meiosis. Thus one can't say, "after 100 of these crosses (or some other number), this cat is now completly the domestic species". Or even 99.9 percent domestic, because the random assortment can't be predicted. I don't know what happens to the unpaired chromosomes in this situation, but it isn't really relevant to the result as far as I can tell. As far as the crossing over, this almost assures that the gamete will have unequal contributions from the genetic material that the parent has inherited. Pschemp 01:21, 20 January 2006 (UTC)
If you keep pouring on chromosomes from one parental species (say, A), you will eventually end up with that species. In the vast number of species, there is no magic mechanism that ensures that it's always chromosomes from species B that make it to the next round! What you should be saying is that you can't be sure of the composition of a particular backcrossed individual, even though you can predict it on average. - Samsara contrib talk 01:56, 20 January 2006 (UTC)
Maybe I shouldn't be applying logic to genetics, but its not my native science field so what the heck. By the way, your edits so far are great. Pschemp 03:18, 20 January 2006 (UTC)
That it tends toward average is exactly right but just as you can't make sure that chromosomes from the B species make it, you can't be sure they didn't make it either and thus you can't say that the result is an A species because that would mean it is 100% A and you can't know that for sure. The probability that there is much B left is low, but it exists, therefore maintaining the individual as a hybrid (technically). You can't make a hybrid into one species by continual crossing. There always exists the possibility (however low) that it contains genetic material from both parental species. Pschemp 02:40, 20 January 2006 (UTC)
Well, if you were really breeding and had enough money to spend, you would "build" genetic markers such as microsatellites, type them in each parental species and then use these genetic markers in the hybrid to determine how much of each species is in it. You would miss some double recombination events happening between markers, but your overall estimate would be very accurate. - Samsara contrib talk 03:48, 20 January 2006 (UTC)
Nice! Something tells me that the people breeding animals in their backyards aren't exactly following that method :) Pschemp 04:09, 20 January 2006 (UTC)

[edit] Hybrid Ratites

Does anybody know of any instance of hybridization between ratites (Emu × Cassowary, Ostrich × Rhea, Greater Rhea × Lesser Rhea, etc.)? I have searched the internet endlessly and have found nothing on the subject. Has it been tried by ratite farmers? If nobody knows, I would at least like to hear opinions on the matter.

Yes. Many hybrids between Greater rhea (Rhea americana) and Lesser Rhea (R. pennata) have occurred in zoos. They are partially fertile. Hybrids have also occurred both in captivity and in a natural setting (i.e., in Kenya) between the Common/Southern Ostrich (camelus) and the Somali Ostrich (molybdophanes), which are usually treated as races of the same species (but occasionally separately). Also, in northern New Zealand, natural hybrids occur between the Brown Kiwi (Apteryx australis) and the Little Spotted Kiwi (A. oweni). See my book (Handbook of Avian Hybrids of the World, Oxford University Press, 2006, p. 39) for documenting references. During the extensive search of the literature I carried out in preparing my book, I found no reports of any intergeneric ratite hybrids, nor did I encounter any mention of attempts to produce such hybrids, although many intergeneric, and even interfamial, bird hybrids are known (see my book). In my opinion, it might be possible to produce an intergeneric ratite hybrid by artificial insemination (e.g., ostrich × rhea). But again, I know of no past attempts to actually do so. Koolokamba (talk) 15:31, 22 January 2008 (UTC) E. M. McCarthy

How about making a contribution to the article, to me the above seems like a book promo and that is not allowed on Wikipedia. Hardyplants (talk) 22:04, 22 January 2008 (UTC)
I see that you have already done that under a IP address, thank you for the corrections and the illustrations. Hardyplants (talk) 22:14, 22 January 2008 (UTC)

It wasn't intended as a book promo. I merely noticed that my book was already being misscited. I wanted to correct the information if I was going to be cited for it. I don't really care whether my book is cited here. The citations could be removed. I'm not sure I would feel comfortable making any further contributions to this article. I would feel I was horning in on whoever has been writing it. It's true, though, that I do see quite a few mistakes. E.M. McCarthy

If you see parts that need further clarification then go ahead and fix them, that is how wikipedia works. I hope you do so and that you stay and contribute in other areas wikepedia too. Hardyplants (talk) 18:30, 23 January 2008 (UTC)

[edit] Interfamilial Hybrids

I added the interfamilial bit to the article & the Domestic Fowl & Guineafowl links and I also added the guineafowl hybrids to the list. The Information is indeed accurate as most classification schemes now classify the guineafowl in its own family, along with 7 other species. The guineafowl is a member of the Numididae and the Chicken & Peafowl are members of the Phaisanidae.

P.S. The wolfdog should be removed from the hybrid list as it is a list of interspecific hybrids and the polar bear & congolese spotted lion hybrids should also be removed as there is already a mention of Ursinae & Panthera hybrids.

[edit] Human/Neanderthal Hybrid

According to this article (http://www.livescience.com/humanbiology/061115_neanderthal_dna.html), there is no evidence for interbreeding of the two species based on a more recent report. So I'm removing that from the listing.

[edit] this page has been vandalized.

Just wanted to note that the first lines of this page have been made into nonsense. "In biology, hybrid has two meanings. Camerons mom likes pasta with heagy as interspecific hybrids or crosses."Geoffointo 19:06, 23 January 2007 (UTC)

[edit] Fungi

We need some stuff about fungi and oomycete hybrids. (Million_Moments 20:27, 15 February 2007 (UTC))

[edit] Merge with Hybrid animals

The article Hybrid animals should be merged into this article. johnpseudo 17:31, 7 March 2007 (UTC)

That seems to have been done in May 2007.--Yannick (talk) 15:36, 24 November 2007 (UTC)

[edit] Hybrid

I think the word Hybrid should direct to the disambiguation page instead of here. I think more & more people mean a hybrid (car) instead of hybrid (animals) when searching with word hybrid. - G3, 07:11, 16 April 2007 (UTC)

I agree. Since there have been no contrary comments since April, I will execute the move.--Yannick (talk) 15:39, 24 November 2007 (UTC)

[edit] Contradiction

The article makes states that wolves and dogs are considered the same species, and as such, hybrids between the two resulting in "wolfdogs" are actually considered non-hybrids. A few lines later, in mentioning the different types of interspecies hybridizations that have been accomplished, there is mention of slective breeding to hybridize different types of dogs.

As different types, or more correctly, breeds, of dogs are actually all included within a single species (Canis familiaris), these dogs would similarly be considered non-hybrids, despite the possibility that they may be referred to as hybrids. DRosenbach (Talk | Contribs) 13:56, 20 December 2007 (UTC)


I removed that statement. 18:47, 20 December 2007 (UTC) —Preceding unsigned comment added by Hardyplants (talk • contribs)
There is still a lack of clarity, in that the term 'hybrid' is being used to mean different things within the same groups of statements. It refers to a cross between species for every statement other than the one about dog breeds, and refers to something else when speaking about interbreed-intraspecies hybridization among dogs. DRosenbach (Talk | Contribs) 03:09, 21 December 2007 (UTC)
Well we could remove all the "fun" animal hybrids and the "interesting" pictures if you think they are confusing. The problem seems to be with the degree of difference, Hybrids between different species show the greatest variation in offspring and thus make for more interesting pictures, hybrids from closely related populations that are very simulare show slight variation (most of the time). 03:19, 21 December 2007 (UTC)Hardyplants (talk) 03:20, 21 December 2007 (UTC)

[edit] contradiction(there is only one tiger species)

An example of an interspecific hybrid is a hybrid between a Bengal tiger and a Siberian tiger. Interspecific hybrids are bred by mating two species, normally from within the same genus. It says an example of interspecific breeding is breeding two species, but the Bengal Tiger and Siberian Tiger are the same species. They are just different sub-species Iamanadam (talk) 17:30, 8 May 2008 (UTC)

Then is should be changed to a Intraspecific hybrid. Hardyplants (talk) 10:52, 16 May 2008 (UTC)