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Chromosomal Disharmony Leads to the Formation of a New Species
furball4paws

Posted on 02/26/2005 3:20:33 PM PST by furball4paws

In 1927, Karpechenko made a hybrid of the common radish, Raphanus sativus, and cabbage, Brassica oleracea. Each parent has a diploid chromosome number of 2N=18. The hybrid also had 18 chromosomes, but because normal sperm and eggs could not be formed, the hybrid was sterile, as is common in such cases.

However, some of the "sterile" hybrids produced a few viable seeds. These seeds were produced when the chromosome number spontaneously doubled. The doubling permitted the pairing of partner chromosomes and the formation of gametes with 1N=18.

Karpechenko witnessed the birth of a new species in the passage of only 3 plant generations. He named the new species Raphanobrassica. It was fully fertile and could not cross with either parent. Unfortunately, the new species had the root of a cabbage and the leaf of a radish, and therefore had no commercial value.

This process of autopolyploidy is responsible for many commercial crop plants (tobacco, for one). It is estimated by botanists that 25-50% of existing plant species arose through a mechanism of autopolyploidy.

References. 1. Niklas, KJ. 1997, The Evolutionary Biology of Plants. University of Chicago Press 2. Karpechenko, GD. 1927. Polyploid hybrids of Raphanus sativus X Brassica oleracea. Zeit. Ind. Abst. Vererbungslehre 48:1-58.


TOPICS: Science
KEYWORDS: chromosomes; crevo; crevolist; evolution; hybrids; plants; speciation
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To: longshadow; PatrickHenry

Oh, goody, are we going to have a party?....


61 posted on 02/25/2006 6:47:12 PM PST by andysandmikesmom
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To: andysandmikesmom
Oh, goody, are we going to have a party?....

The good news is : YES, we're having a party....

... the bad news is they forgot to tell you: you're the HUMAN SACRIFICE!

;-)

62 posted on 02/25/2006 6:52:51 PM PST by longshadow (FReeper #405, entering his ninth year of ignoring nitwits, nutcases, and recycled newbies)
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To: longshadow

Help....


63 posted on 02/25/2006 6:53:31 PM PST by andysandmikesmom
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To: andysandmikesmom
Help....

I suppose you could petition the Grand Master to tranfer you to the janitorial pool instead..... it's about 6 of one and half dozen of the other.

64 posted on 02/25/2006 6:55:31 PM PST by longshadow (FReeper #405, entering his ninth year of ignoring nitwits, nutcases, and recycled newbies)
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65 posted on 02/25/2006 6:55:48 PM PST by CarolinaGuitarman ("There is grandeur in this view of life...")
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To: longshadow
[We now have over 350 names, so we've gained 110 in a year.] Do you realize, that's a growth rate of over 45% per year?

Clearly, freepers are abandoning evolution in droves. The inexorable logic and dazzling science demonstrated by the creationists, to say nothing of their calm and deliberate demeanor, has taken a terrible toll on our ranks.

66 posted on 02/25/2006 6:59:29 PM PST by PatrickHenry (Virtual Ignore for trolls, lunatics, dotards, scolds, & incurable ignoramuses.)
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To: ml/nj
,i>But if plants need insects to pollinate to reproduce, isn't this a problem?

No. Why do you assume that early plants must use the same mechanism (insects) as modern ones?

67 posted on 02/25/2006 7:00:30 PM PST by Doctor Stochastic (Vegetabilisch = chaotisch ist der Charakter der Modernen. - Friedrich Schlegel)
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To: CarolinaGuitarman

Where's the Chac Mol?


68 posted on 02/25/2006 7:06:13 PM PST by Doctor Stochastic (Vegetabilisch = chaotisch ist der Charakter der Modernen. - Friedrich Schlegel)
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To: longshadow; PatrickHenry

Hey now, I thought I got some sort of dinner with the Grand Master, because I once got into an argument with JackChick, and wound up banned on another site because of it...

Is this my reward, to be the human sacrifice?

I thought I was going to get to drink with the Grand Master, and now I have to push a broom...how I have sunk so low..(sniffle, sniffle)


69 posted on 02/25/2006 7:09:10 PM PST by andysandmikesmom
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To: PatrickHenry

Spaghetti legs, no doubt.


70 posted on 02/25/2006 7:11:39 PM PST by js1138
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To: andysandmikesmom
Hey now, I thought I got some sort of dinner with the Grand Master, because I once got into an argument with JackChick, and wound up banned on another site because of it...

The Grand Master has not forgotten your service to the cause. Be assured that the festivities will be enjoyable. (If that sounds cryptic, that's how he talks.)

71 posted on 02/25/2006 7:11:42 PM PST by PatrickHenry (Virtual Ignore for trolls, lunatics, dotards, scolds, & incurable ignoramuses.)
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To: PatrickHenry

Ah, thanks for remembering...the GrandMaster is good....being cryptic is quite interesting...


72 posted on 02/25/2006 7:14:51 PM PST by andysandmikesmom
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To: PatrickHenry
The inexorable logic and dazzling science demonstrated by the creationists, to say nothing of their calm and deliberate demeanor, ...

I've always been impressed by the gentle, self-deprecating humor...

...and the almost obsessive eagerness to acknowledge errors, or even things that just appear to be erroneous on first sight.

73 posted on 02/25/2006 7:19:19 PM PST by Virginia-American
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To: Virginia-American
...and the almost obsessive eagerness to acknowledge errors ...

That certainly adds to the general impression of credibility and integrity. Very impressive.

74 posted on 02/25/2006 7:22:32 PM PST by PatrickHenry (Virtual Ignore for trolls, lunatics, dotards, scolds, & incurable ignoramuses.)
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To: furball4paws
"Chromosomal Dissonance" would have been a more melodic title.
75 posted on 02/25/2006 7:36:39 PM PST by Doctor Stochastic (Vegetabilisch = chaotisch ist der Charakter der Modernen. - Friedrich Schlegel)
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To: PatrickHenry

Next time Bipolar Bob logs on, he is going to see several posts addressing something he said over a year ago, and wonder WTH is going on.


76 posted on 02/25/2006 10:29:48 PM PST by Ken H
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To: furball4paws

But they're still Russians!


77 posted on 02/26/2006 1:46:21 AM PST by dread78645 (Intelligent Design. It causes people to misspeak)
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To: Doctor Stochastic
Why do you assume that early plants must use the same mechanism (insects) as modern ones?

I guess I just did. (Your comment here is to a post I made one year ago.)

Certainly any that rely solely on insects for polination could not begin to "evolve" into other types of plants until there would be insects around.

ML/NJ

78 posted on 02/26/2006 6:23:07 AM PST by ml/nj
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To: PatrickHenry

Well, we got just as much from the second "Error" ping as the first. Maybe we should dust off some other old threads?


79 posted on 02/26/2006 7:00:09 AM PST by furball4paws (Awful Offal)
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To: andysandmikesmom

Don'y worry. The Grand Master is just an old 6502 collecting dust. If you can sleep standing up, you've got it made.


80 posted on 02/26/2006 7:02:42 AM PST by furball4paws (Awful Offal)
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