laporan genetika giant chromosome
TRANSCRIPT
RATIFICATION PAGE
Complete report of Genetics & Evolution with the title is “ Giant
Chromosome”, which made by :
name : Syaiful Bakhri
reg. no : 081 404 192
group : III
Have been checked and consulted by Assistant and Assistant Coordinator and
this report is accepted.
Makassar, December 3th, 2010
Assistant Coordinator,
Misnawati S.Si
Assistant,
Djumarirmanto S.pd
Known by
Lecturer of Responsibility,
Hartati, S.Si, M.SiReg No : 1974040520000032002
CHAPTER IINTRODUCTION
A. Background
Genetics is already on the heritage and diversity characteristics of an
organism, whether it is unicellular and multicellular organisms. Research in the
field of genetics have been analyzed for the level monocular ribonucleic acid
(DNA) is a chemical substance that builds a chromosome as a substance which
fell. Most which has been discovered about the molecular structure of DNA and
also replication. Each unicellular and multicellular organisms have a somewhat
different form in terms of both size and composition, but all fixed chromosomes
were prepared by the DNA. Chromosome contained in each cell primarily in the
nucleus of a cell organism. Chromosomes can be observed with a microscope
with a magnification tool that is certain. Chromosome-chromosome derived from
the female parent male-like shape of so-called homologous chromosomes pair and
the number of cells in the body called the diploid (2n), sex cells contain only half
the number of chromosomes found in cells somatic limiting the number of
chromosomes is called haploid.
Chromosomes derived from the female parent with a similar shape from
male parent. Then a pair of chromosomes are called homologous chromosomes.
Therefore in body called diploid chromosome number (2n). sex cells (gametes)
contain only half the chromosomes found in somatic cells. Because the number of
chromosomes in gametes is called the haploid (n). single cell from a species
namely haploid genome. The number of chromosomes possessed a variety of
creatures never an equal. But the number of chromosomes possessed every living
thing in general does not change during his life. As human beings and cattle 46
chromosomes 60.
In order to better understand the structure and can saw firsthand that there
are giant chromosomes in fruit flies (Drosophila melanogaster), the practicum is
held. With fruit fly larvae use estimated at instars phase three we can see the
structure of the giant chromosome.
B. Purpose
This practicum aimed to observe the giant chromosome contained in the larval fruit fly (Drosophila melanogaster).
C. Benefit The benefit of this lab is, students can learn how to make fresh
preparations of the salivary gland cells of fruit flies, and can observe the light
Drosophila melanogaster chromosome.
CHAPTER IIPREVIEW OF LITERATURE
In addition to increasing the volume of the cell's nuclei and causing cell
expansion, polytene cells may also have a metabolic advantage as multiple copies of
genes permits a high level of gene expression. In Drosophila melanogaster, for
example, the chromosomes of the larval salivary glands undergo many rounds of
endoreplication, to produce large amounts of glue before pupation. Polytene
chromosomes have characteristic light and dark banding patterns which can be used
to identify chromosomal rearrangements and deletions. Dark banding frequently
corresponds to inactive chromatin, while light banding is usually found at areas with
higher transcriptional activity. The banding patterns of the polytene chromosomes of
Drosophila melanogaster were sketched in 1935 by Calvin B. Bridges, in such detail
that his maps are still widely used today. The banding patterns of the chromosomes
are especially helpful in research, as they provide an excellent visualization of
transcriptionally active chromatin and general chromatin structure( Anonyma,2010)
Polytene chromosomes are found in the salivary glands malpighian tubules,
gut, etc. of Drosophila and Chironomuslarva. These chromosomes show swellings
here and there. These swellings of double Polytene chromosomes are called puffs or
balbiani rings.The study of puffing pattern offers the following conclusion:
1. Puffs are the regions of gene activity. in the puffs mRNA transcription occurs
actively.
2. The positions of puffs are different in different tissues at any one timeChanges
in puffs of giant chromosomes of Drosophila hyder salivary during
development.
3. The positions of puffs are different in the same tissue at different stages of
development.
4. At any one time, all the cells of any one tissue show the same pattern of
puffing.
5. A particular puff produces a particular type of protein. (Anonymb,2010)
During the early period of genetics, the search for mutants was a slow, tedious
procedure dependent on the spontaneous appearance of altered genes, In 1927, using
a special strain of fruit flies designed to reveal the presence of recessive alleles, H.J.
Muller found the files subjected to a sublethal dose of X-rays displayed more than
100 times nthe spontaneous mutation rate exhibited by nonirradiated controls. This
finding had important consequence. On the practical side, the use of mutagenis
agents, such as X-rays and ul;traviolet radiation, greatly increased the number of
mutant available for genetic research. The finding also pointed out the hazard of the
increasing use of radiation in the industrial and medical fields. Today, mutation in
Drosphilla melanogaster are most often generated by adding a chemical mutagen
( ethyl methane sulfonate ) to the animals feed (Gerald,1987)
A second type of giant chromosome. Occurs in the mid-prophase of meiosis
in the oogenesis of certain animals. OOcyte nuclei are almost always large, and
perhaps especially so in groups with yolky eggs. It is apparently when such nuclei
occur in species with high DNA values thet we are apt to get giant chromosome of
the ‘lampbrush’ type-so called from their imagined resemblance to the brushes used
to clean old fashioned oil-lamp chimneys. It is fairly clear, however, that these
chromosome do not really constitute an entirely distinct type, but are merely extreme
examples of the more usual type of mid prophase chromosome in oogenesis
(Edward,2005).
Structure of these ‘ giant chromosome’ and their relationship to regular
mitotic chromosome but the “polytene hypothesis” originally proposed by Koltzoff
(1943) and modified buy Bauer (1953), is now fully accepted ( Bauer and Beerman,
1952; Beermann (1962) may be consulted for a complete consideration of the
evidence as the following is only a brief account. Polytene chromosome developed
from the chromosome of diploid nuclei by successive duplication of each
chromosome element. Usually the homologous chromosome pair early during this
process and remain paired throughout polytenization. The chromosome duplication
involved differs from that typical of a normal mitotic cycle in many respect. The
homologues remain paired . the chromosome fail to participate in the normal mitotic
cycle of coiling remain intimately paired with each other at the end of each
replication cycle and the nuclear membrane and nucleoli remain intact throughout the
replication cycles (Beament, 2007).
The chromosomal locations of several satellite DNAs have been determined
by a technique called in situ hybridization. It involves annealing single strands of
isolated radioactive satellite DNA directly to denatured DNA in chromosome squash
preparation. After washing out the non hybridized radioactive material, the location
of the satellite DNA sequences in chromosome determined by autoradiography.
Satellite DNA are usually in heterochromatic regions of the chromosomes, of the
around centromeres and nearstelomeres, and are not transcribed into RNA. Other
kinetically distinguished classes of DNA are they moderately repetitive and unique
DNA (Pragya,1989).
In the following we describe first the principle of the classic approach to gene
localization as introduced by Morgan and his followers. This provides an opportunity
to introduce some general concepts. We then discuss statistical methods for detecting
and measuring linkage in humans. The various groups of DNA markers are describe
next, followed by the principle of cell fusion and its use in localizing genes on
chromosomes, as well as the application of radioactive and no isotopic in situ
hybridization for this purpose. Genetics maps are compared to physical maps. And
the use of linkage studies as analytical tools in genetic analysis of common diseases
with complex etiology and pathogenesis (Vogel, 1954).
The formation of giant chromosome is characterized by marked variations in
the degree of the chromosome close attachment : from a complete association of
chromosome along the entire length of the chromosome in suspensor to a local
attachment in heterochromatic areas of the antipodes and ceelsa of the haustorium . In
the antipode cells for instance, several nuleus types are described those with
despiralized chromosome bound in heterochromatid block areas, those with many
decondensed isolated chromatin fibrils, those with separately located
endochromosomes and those with giant chromosome in which the chromatids are
attached to each other along almost the entire chromosome length (kwang.1989).
CHAPTER IIIMETHODE PRAKTICUM
A. Time and Place
Day / Date : Friday / November 26th 2010
Time : 13.00 a.m. until 15.00 a.m.
Place : Biology Laboratory IInd floor West FMIPA UNM Makassar
B. Tool and Material
1. Tools
a. Electron microscope
b. Light Microscope
c. Object glass
d. Deck glass
e. Razor blade
f. Bunsen
g. Pipette
2. Materials
a. Physiological NaCl
b. Instars of fruit flies (Drosophila melanogaster)
c. Asetokarmin
C. Work procedure
1. Choosed the larvae are large, then dripped glass preparations with
physiological NaCl.
2. Flies that have been drugged take slowly by using tweezers and then save in a
petri dish.
3. Dissected instar on preparations glass then dissect the head.
4. Dripped with asetokarmin
5. Closed with a deck glass and then pressed.
CHAPTER IVOBSERVATION RESULT AND DISCCUSSION
A. Observation result
Giant Chromosome Notes :
1. Chromosome
2. Centromer
3. Arm
B. Discussion
In the results as observed in Drosophila melanogaster, in which the anterior
part of larval salivary glands have to be observed how the shape of giant
chromosomes contained therein. Before making observations under the microscope
first salivary glands that have been taken in the anterior part of larvae is pressed with
glass objects for the salivary glands can glass or destroyed, so that the cells spread to
facilitate the observation. In addition, fresh preparations were poured with
asetokarmin then by using Bunsen. The purpose is to clarify the provision
asetokarmin chromosome. While aiming to preparate fixation performed on the glass
object.
Typical of giant chromosomes are there handcuffs, ribbon and bright gsri
regularly arranged alternately. Ribbon light on this chromosome is eukromatin with
winding tenuous. While the dark band is winding heterokromatin with a solid and can
undergo condensation. DNA is generally found in dark bands. The part that plays an
active role in the division is part of the ribbon to kromsom X, 1032 krmosom ribbon
on the second, 1047 the ribbon on the third chromosome and 34 on chromosome band
on the fourth chromosome. So the total is 2650 to ribbon one genome. In several
studies mentioned that the number of tape is 3286.
Giant chromosomes of Drosophila melanogaster is an interphase
chromosome and more elongated than metaphase chromosomes. Because they can be
viewed at the time of interphase chromosomes, while not unusual, because they are
the result of repeated duplication of krmosom without cell division. Homologous
duplication duplication-both paternal and internal location perfectly side by side.
CHAPTER VCONLUSSION AND SUGESSTION
A. Conclusion
Based on the observations we can conclude that the giant chromosomes are
chromosomes found in Drosophila melanogaster salivary glands, which has a
structure that is larger and longer than normal body chromosomes.
B. Suggestion
a. For Laboratory
1. Laboratory should prepare complete equipment and materials which will be
use in practicum, so easy for practicant to done the practicum.
2. Laboratory should complete the practicum rooms with air conditioner or
fan so make practicant glad to be in laboratory.
b. For Practicant
1. Practicant should prepare anything they need before enter into laboratory,
so they will easy to done practicum.
2. Practicant should work together with teammate, so practicum will be
faster and the result.
BIBLIOGRAPHY
Anonyma.2010.Giant chromosome. http://en.wikipedia.org/wiki.
Anonymb. 2010. giant chromosome http://www.unjabisnis.com/2009/12/\sex influence gene \.html
Edward willets.2005. Genetic demystified. New York : MC Graw hill
Gerald karp 1987,cell and molecular biology. New York: brooks Cole
J.W.L. Beament.2007. Advances in insect physiology. New York: Humana Press
Kwang w. jeon.1989.international review of cytology. New York: Academic press
Pragya.khanna.1989.essentials of genetic. New York: Greenwood publishing group
Vogel and motulsky’s.1954.human genetic. New York: Academic Press
anonyma
Polytene chromosomeFrom Wikipedia, the free encyclopediaJump to: navigation, search
Polytene chromosomes in a Chironimus salivary gland cell
Polytene chromosome
Polytene chromosomes from Axarus larva
To increase cell volume, some specialized cells undergo repeated rounds of DNA replication
without cell division (endomitosis), forming a giant polytene chromosome. Polytene chromosomes form when multiple rounds of replication produce many sister chromatids that remain synapsed together. Polytene chromosomes were originally observed in the larval salivary glands of Chironomus midges by Balbiani in 1881.[1]
In addition to increasing the volume of the cell's nuclei and causing cell expansion, polytene cells may also have a metabolic advantage as multiple copies of genes permits a high level of gene expression . In Drosophila melanogaster , for example, the chromosomes of the larval salivary glands undergo many rounds of endoreplication , to produce large amounts of glue before pupation .
Polytene chromosomes have characteristic light and dark banding patterns which can be used to identify chromosomal rearrangements and deletions. Dark banding frequently corresponds to inactive chromatin, while light banding is usually found at areas with higher transcriptional activity. The banding patterns of the polytene chromosomes of Drosophila melanogaster were sketched in 1935 by Calvin B. Bridges , in such detail that his maps are still widely used today. The banding patterns of the chromosomes are especially helpful in research, as they provide an excellent visualization of transcriptionally active chromatin and general chromatin structure.
Chromosome puffs are diffused uncoiled regions of the polytene chromosome that are sites of RNA transcription. A Balbiani ring is a large chromosome puff.
Polytene chromosomes were originally observed in the larval salivary glands of Chironomus midges by Balbiani in 1881, but the hereditary nature of these structures was not confirmed until they were studied in Drosophila melanogaster in the early 1930s by Emil Heitz and Hans Bauer. They are known to occur in secretory tissues of other dipteran insects such as the Malpighian tubules of
Sciara and also in protists, plants, mammals, or in cells from other insects. Some of the largest polytene chromosomes described thus far (see scale bar in figure below) occur in larval salivary gland cells of the Chironomid genus Axarus.
Another form of chromosomal enlargement that provides for increased transcription is the lampbrush chromosome.
Polytene chromosomes are also used to identify the species of Chironomid larvae that are notoriously difficult to identify. Each morphologically distinct group of larvae consists of a number of morphologically identical (sibbling) species that can only be identified by rearing adult males or by cytogenetic analysis of the polytene chromosomes of the larvae. Karyotypes are used to confirm the presence of specific species and to study genetic diversity in species with a wide range.[2][3]
Anonymb
Puffing Pattern in Polytene ChromosomesPolytene chromosomes are found in the salivary glands malpighian tubules, gut, etc. of Drosophila and Chironomuslarva. These chromosomes show swellings here and there. These swellings of double Polytene chromosomes are called puffs or balbiani rings.
The study of puffing pattern offers the following conclusion:1. Puffs are the regions of gene activity. in the puffs mRNA transcription occurs actively.2. The positions of puffs are different in different tissues at any one time
Changes in puffs of giant chromosomes of Drosophila hyder salivary during development.
3. The positions of puffs are different in the same tissue at different stages of development.4. At any one time, all the cells of any one tissue show the same pattern of puffing.5. A particular puff produces a particular type of protein.
Puffing is induced by ecdysone, metamorphosis. When this hormone is injected into the larva in the last instar stage (this instar converts the larva into pupa), the larva develops puffing pattern similar to that develops during pupation. The puffing pattern clearly demonstrates that only a particular set of genes are made active in a tissue a particular time.