Term Location r (arm ratio) (Long arm/Short arm)
M median point 1 .0
m median region 1.0-1.7
sm submedian region 1.7-3.0
st subterminal region 3.0-7.0
t terminal region 7.0-∞
T terminal point ∞
bu oranları zaten biliyorum Fahim bey....balık sitogenetiğinde m-sm ve st-a var....
bunların oranını araştırıyorum....
Dear Serkan
In Brazil we do not adopt the telocentric type because we understand that there will always be a short arm, no matter how small. Thus, we adopt the class of acrocentric chromosomes (> or = 7.0) replacing telocentrics.
I didn't understand your dialogue with Fahim, but noticed he showed ratio of arms in accordance with the proposal of Levan. A major highlight is that the representation of chromosomal classes in capital letters should be used only when the ratio of arms is accurate. For all other situations must be written in lowercase letters.
All the best
Roberto
Dear Roberto,
I know how to describe the chromose according to Levan et al. by measuring wtih MM. But I can't understand this type chromosome is different and not clearly revealling any infos about this.....is meaning m-sm or st-a terms meta-submetacentric or telo-akrosecntric chromosom or another meaning? I want to earn...and we understand how ratio differ from the Levan's raitos,anyway?....I talk to him with Turkish, I am sure that he is a student in Turkish univ. I talk to him same things, talk to you, too.
sincerely.
Dear Serkan
I believe that now I could better understand your question. Communication is difficult in a language that is not our native language. Sorry this my difficulty.
The classification of chromosomal types is really problematic. I think the biggest problem is cause misleading inferences, especially in the aspect of karyotype evolution in fish. I myself have used in the past the union of metacentric class with submetacentrics (m-sm) and subtelocentric with acrocentric (st-a) in a group of fish with great variation interspecific karyotype. In this fish, sometimes chromosomal measures were within the limits of reason of arms or could not consensu between different karyotypes used to establish the pattern of occurrence. Thus, we believe, in time, be better join the classes so as not to throw uncertain data in the literature.
Today, even with the technical limitations, I prefer to define the chromosomal classes separately.
All the best.
Roberto
Dear Roberto,
Thank you very much for answering me...I think that this problem is neither mine nor you, all cytogenetics interesting with fish chromosome of. I apologise from you, but your sending is not anwer my question. How to measure? How to describe? According to what differ? this is derived from Levan's result, Maybe Klinkhardt et al. are released some aspects on this in his book, named "Database on Fish Chromosome", as you known. But they have revealed the chromosome types as the NOR bearings on. Still does not solve my problem. I have difficulty to explain this anywhere/any meetings to my colleagues, knowing or not knowing the subject.
I think to write a review on this subject, hereby I may stand out in relief on this, what do yo think my opinion?
I research on chromosomal evolution of fishes, I run accross alot of interestings in fishes, because researchers say that does not keep the other....
sincerely yours
serkan
Dear Serkan, Maybe do you refer to ´what defines the classification m-sm or st/a´?
"when the 95% confidence limits of the centromeric index mean covered two chromosome categories a binary terminology was adopted" (Insua et al., 2006; Genetica (2006) 126: 291–301."
- Badges
- Science method