Human chromosomes, Biology

HUMAN CHROMOSOMES

The normal diploid (2N) chromosome number in human being is 46.

It was given by T.H. Tjio and A. Levan in 1956.

The chromosome complement of a cell depicting the number, size and form of the chromosome as seen in metaphase of mitosis is called karyotype.

The chromosomes are morphologically numbered into 7 groups. (size and position of centromere) by Denver and Colorado (1960)

Group (A)            : 1-3 chromosomes of largest size and submetacentric or metacentric centromere.

Group (B)            : 4-5 chromosomes with less larger size, submetacentric

Group (C)            : 6-12 chromosomes with medium sized and submetacentric centromere.

Group (D)            : 13-15 chromosomes, shorter than group 'c' with centromere near the end (Arcocentric). They are sat chromosomes or satellite.

Group (E)            : 16-18 chromosomes, short sized, with median or submedian centromere.

Group (F)            : 19-20 chromosomes, short sized with median centromere.

Group (G)           : 21-22 chromosomes, smallest in size, Acrocentric and are also satellites.

X chromosome is placed in 'C' group due to its larger size and submedian centromere and Y-chromosome is placed in group 'G' due to its short size and terminal centromere.

Posted Date: 10/8/2012 3:27:26 AM | Location : United States







Related Discussions:- Human chromosomes, Assignment Help, Ask Question on Human chromosomes, Get Answer, Expert's Help, Human chromosomes Discussions

Write discussion on Human chromosomes
Your posts are moderated
Related Questions
Comparison of CABG and Angioplasty :  Results of six major randomized clinical trials of multi vessel angioplasty Vs CABG are now available. The main conclusions are: Patient

write about the asexual reproduction in mucor

Q. Symptoms of dyspepsia? The life style modification in terms of work schedules, eating behaviour like consuming meals when extremely tired, quitting alcohol and smoking would

Define Protein Concentrates, Isolates and Hydrolysates? The first question that may come to your mind is why do we need to concentrate or isolate a protein from a product? The

what the advantage of yersinia pestis

Define role of Vitamin K in controlling gene expression? Prithrombin, a protein required for blood clotting is assembled with a large number of glutamic acid residues. In the p

Q. What is the kind of circulatory system present in annelids? In beings of the phylum Annelida the circulatory system is closed that is blood circulation takes place only with

(i)        Area uses or permit exposure to radiation should be Marked' Restricted Area 'or Radiation zone etc. (ii)        Avoid x-rays of chest and lower back in routine physic

Q. What is hematosis? In humans where does hematosis occur? Hematosis is the oxygenation of the blood, venous blood (oxygen-poor) after hematosis is transformed into arterial b

Q Why do protease-supplying cells of the stomach and of the pancreas make only precursors of the active proteolytic enzymes? The stomach and the pancreas make zymogens of the p