Chromosomal aberrations arise from structural changes or alterations in chromosome number. There are two main types of chromosomal aberrations: structural aberrations which involve changes in chromosome structure, and numerical aberrations which involve changes in chromosome number. Common types of structural aberrations discussed in the document include deletions, duplications, inversions, and translocations. Deletions involve the loss of a chromosome segment, duplications the addition of an extra segment, inversions reverse the orientation of a segment, and translocations involve segments moving to new chromosomes. These structural changes can have varying genetic effects depending on the location and size of the alteration.
Structural Chromosomal aberrations (Change in Structure of Chromosome)Asad Afridi
this presentation is about chromosomal aberration especially change in structure of chromosome. different types of structural chromosomal aberrations are also discussed. effects of different aberration are also included.
Inability of a plant with functional pollen to set seed when self-pollinated.
Hindrance to self-fertilization.
Prevents inbreeding and promotes outcrossing.
Reported in about 70 families of angiosperms including crop species.
Structural Chromosomal aberrations (Change in Structure of Chromosome)Asad Afridi
this presentation is about chromosomal aberration especially change in structure of chromosome. different types of structural chromosomal aberrations are also discussed. effects of different aberration are also included.
Inability of a plant with functional pollen to set seed when self-pollinated.
Hindrance to self-fertilization.
Prevents inbreeding and promotes outcrossing.
Reported in about 70 families of angiosperms including crop species.
The brief note on B-Chromosomes with characteristics and research case studies.
This particular studies has more scope for further experimental evidences.
It is the fundamental law of population genetics and provides the basis for studying Mendelian populations ( Mendelian population: A group of sexually inbreeding organisms living within a circumscribed area). It describes populations that are not evolving.
This PPT consists of 15 slides only explaining Pleiotropy. This is a phenomenon when one gene controls more than one trait , the traits may be related .Generally one gene's product acts for many reactions and so can affect more than one trait. Examples can be seen in pea Coloured flower and pigmentation in leaf axil, frizzle trait in chicken, fur colour and deafness in cats,Human pleiotropic traits are PKU,Sickle cell Anaemia. HOsyndrome , p53 gene etc
The brief note on B-Chromosomes with characteristics and research case studies.
This particular studies has more scope for further experimental evidences.
It is the fundamental law of population genetics and provides the basis for studying Mendelian populations ( Mendelian population: A group of sexually inbreeding organisms living within a circumscribed area). It describes populations that are not evolving.
This PPT consists of 15 slides only explaining Pleiotropy. This is a phenomenon when one gene controls more than one trait , the traits may be related .Generally one gene's product acts for many reactions and so can affect more than one trait. Examples can be seen in pea Coloured flower and pigmentation in leaf axil, frizzle trait in chicken, fur colour and deafness in cats,Human pleiotropic traits are PKU,Sickle cell Anaemia. HOsyndrome , p53 gene etc
The following presentation is only for quick reference. I would advise you to read the theoretical aspects of the respective topic and then use this presentation for your last minute revision. I hope it helps you..!!
Mayur D. Chauhan
Metals accumulation and As releasing during interaction of clay and iron mine...Agriculture Journal IJOEAR
Abstract— The soil and sediment samples with different content of metals and clay minerals were investigated during bioleaching. The increasing of clay and metal concentrations with decreasing particle size were found both in contaminated soil and sediment. Heterotrophic bioleaching of the iron rich clay fractions from the soil and the sediment were evaluated for his effectiveness in the cycling of iron bound As by consuming organic nutrients. The treatment involved the use of the indigenous bacteria, whose activity was combined with the chelating strength of EDDS, SDS, Na4P2O7 and fertilizers. Heterotrophic bacteria caused decomposition of iron binding deposition as is adsorption on clay with followed dissolving of Fe mainly by the sediment bioleaching. The concentration of iron decreased by precipitation with As sorption after 19 days of sediment bioleaching. The Cu and Zn extraction was inhibited by bioleaching during the iron and arsenic dissolution and precipitation. By contrast, the additives 3mM Cu and 3mM Zn were applied into medium and thus affected the activity of soil resistant heterotrophic bacteria with followed increasing of the iron and arsenic extraction by the soil clay bioleaching. Therefore, this study confirmed the soil and sediment bioleaching in Fe or As releasing efficiency under different conditions regulated by indigenous bacteria. The bioleaching can be a suitable technology for As removal from the untreated soil and sediment by stimulation of the resistant bacteria activity. The separation of clays from the soil and sediment samples did not decreased of toxic element limits because clay and iron minerals coated on coarse silicate particles and the clay fraction is bearers of metals which contaminate the soil and sediment environment.
The French Revolution, which began in 1789, was a period of radical social and political upheaval in France. It marked the decline of absolute monarchies, the rise of secular and democratic republics, and the eventual rise of Napoleon Bonaparte. This revolutionary period is crucial in understanding the transition from feudalism to modernity in Europe.
For more information, visit-www.vavaclasses.com
Students, digital devices and success - Andreas Schleicher - 27 May 2024..pptxEduSkills OECD
Andreas Schleicher presents at the OECD webinar ‘Digital devices in schools: detrimental distraction or secret to success?’ on 27 May 2024. The presentation was based on findings from PISA 2022 results and the webinar helped launch the PISA in Focus ‘Managing screen time: How to protect and equip students against distraction’ https://www.oecd-ilibrary.org/education/managing-screen-time_7c225af4-en and the OECD Education Policy Perspective ‘Students, digital devices and success’ can be found here - https://oe.cd/il/5yV
The Art Pastor's Guide to Sabbath | Steve ThomasonSteve Thomason
What is the purpose of the Sabbath Law in the Torah. It is interesting to compare how the context of the law shifts from Exodus to Deuteronomy. Who gets to rest, and why?
Palestine last event orientationfvgnh .pptxRaedMohamed3
An EFL lesson about the current events in Palestine. It is intended to be for intermediate students who wish to increase their listening skills through a short lesson in power point.
The Roman Empire A Historical Colossus.pdfkaushalkr1407
The Roman Empire, a vast and enduring power, stands as one of history's most remarkable civilizations, leaving an indelible imprint on the world. It emerged from the Roman Republic, transitioning into an imperial powerhouse under the leadership of Augustus Caesar in 27 BCE. This transformation marked the beginning of an era defined by unprecedented territorial expansion, architectural marvels, and profound cultural influence.
The empire's roots lie in the city of Rome, founded, according to legend, by Romulus in 753 BCE. Over centuries, Rome evolved from a small settlement to a formidable republic, characterized by a complex political system with elected officials and checks on power. However, internal strife, class conflicts, and military ambitions paved the way for the end of the Republic. Julius Caesar’s dictatorship and subsequent assassination in 44 BCE created a power vacuum, leading to a civil war. Octavian, later Augustus, emerged victorious, heralding the Roman Empire’s birth.
Under Augustus, the empire experienced the Pax Romana, a 200-year period of relative peace and stability. Augustus reformed the military, established efficient administrative systems, and initiated grand construction projects. The empire's borders expanded, encompassing territories from Britain to Egypt and from Spain to the Euphrates. Roman legions, renowned for their discipline and engineering prowess, secured and maintained these vast territories, building roads, fortifications, and cities that facilitated control and integration.
The Roman Empire’s society was hierarchical, with a rigid class system. At the top were the patricians, wealthy elites who held significant political power. Below them were the plebeians, free citizens with limited political influence, and the vast numbers of slaves who formed the backbone of the economy. The family unit was central, governed by the paterfamilias, the male head who held absolute authority.
Culturally, the Romans were eclectic, absorbing and adapting elements from the civilizations they encountered, particularly the Greeks. Roman art, literature, and philosophy reflected this synthesis, creating a rich cultural tapestry. Latin, the Roman language, became the lingua franca of the Western world, influencing numerous modern languages.
Roman architecture and engineering achievements were monumental. They perfected the arch, vault, and dome, constructing enduring structures like the Colosseum, Pantheon, and aqueducts. These engineering marvels not only showcased Roman ingenuity but also served practical purposes, from public entertainment to water supply.
Synthetic Fiber Construction in lab .pptxPavel ( NSTU)
Synthetic fiber production is a fascinating and complex field that blends chemistry, engineering, and environmental science. By understanding these aspects, students can gain a comprehensive view of synthetic fiber production, its impact on society and the environment, and the potential for future innovations. Synthetic fibers play a crucial role in modern society, impacting various aspects of daily life, industry, and the environment. ynthetic fibers are integral to modern life, offering a range of benefits from cost-effectiveness and versatility to innovative applications and performance characteristics. While they pose environmental challenges, ongoing research and development aim to create more sustainable and eco-friendly alternatives. Understanding the importance of synthetic fibers helps in appreciating their role in the economy, industry, and daily life, while also emphasizing the need for sustainable practices and innovation.
This is a presentation by Dada Robert in a Your Skill Boost masterclass organised by the Excellence Foundation for South Sudan (EFSS) on Saturday, the 25th and Sunday, the 26th of May 2024.
He discussed the concept of quality improvement, emphasizing its applicability to various aspects of life, including personal, project, and program improvements. He defined quality as doing the right thing at the right time in the right way to achieve the best possible results and discussed the concept of the "gap" between what we know and what we do, and how this gap represents the areas we need to improve. He explained the scientific approach to quality improvement, which involves systematic performance analysis, testing and learning, and implementing change ideas. He also highlighted the importance of client focus and a team approach to quality improvement.
Welcome to TechSoup New Member Orientation and Q&A (May 2024).pdfTechSoup
In this webinar you will learn how your organization can access TechSoup's wide variety of product discount and donation programs. From hardware to software, we'll give you a tour of the tools available to help your nonprofit with productivity, collaboration, financial management, donor tracking, security, and more.
2. Chromosomal Aberrations
• The somatic (2n) and gametic (n) chromosome numbers of a
species ordinarily remain constant.
• This is due to the extremely precise mitotic and meiotic cell
division.
• Somatic cells of a diploid species contain two copies of each
chromosome, which are called homologous chromosome.
• Their gametes, therefore contain only one copy of each
chromosome, that is they contain one chromosome complement or
genome.
• Each chromosome of a genome contains a definite numbers and
kinds of genes, which are arranged in a definite sequence.
• Sometime due to mutation or spontaneous (without any known
causal factors), variation in chromosomal number or structure do
arise in nature. - Chromosomal aberrations.
• Chromosomal aberration may be grouped into two broad classes:
1. Structural and 2. Numerical 2
3. INTRODUCTION:
• Chromosome structure variations result from
chromosome breakage.
• Broken chromosomes tend to re-join; if there is more
than one break, rejoining occurs at random and not
necessarily with the correct ends.
• The result is structural changes in the chromosomes.
• Chromosome breakage is caused by X-rays, various
chemicals, and can also occur spontaneously.
• There are four common type of structural aberrations:
1.Deletion or Deficiency,
2.Duplication or Repeat
3.Inversion, and
4.Translocation 3
4. DELETION OR DEFICIENCY
Loss of a chromosome segment is known as deletion
or deficiency
It can be terminal deletion or interstitial or
intercalary deletion.
A single break near the end of the chromosome
would be expected to result in terminal deficiency.
If two breaks occur, a section may be deleted and an
intercalary deficiency created.
Terminal deficiencies might seem less complicated.
But majority of deficiencies detected are intercalary
type within the chromosome.
Deletion was the first structural aberration detected
by Bridges in 1917 from his genetic studies on X
chromosome of Drosophila. 4
6. 6
Chromosome with deletion can never revert back to a normal
condition and transmitted to next generation.
In intercalary deletion, broken acentric fragment of
chromosomes appear as small chromatin bodies in cells known
as Micronuclei.
Homozygous deletion is lethal.
Heterozygous deletions can revealed a phenomenon known as
Pseudodominance /
One copy of a gene is deleted
So the recessive allele on the other chromosome is now
expressed
Eg., sex linked lethal and dominant notch-wing etc. in
Drosophila.
Cri-du-chat (Cat cry syndrome) of babies results from the
chromosome deficiency in the short arm of chromosome 5 .
7. 7
•Deletion can be recognized during meiotic pairing of
homologus chromosome and during somatic pairing in
specialized tissue like salivary gland of Drosophila or during
pachytene in Maize.
•Due to intercalary deletion unpaired loop is formed.
8. DUPLICATION
The presence of an additional chromosome
segment, as compared to that normally present in a
nucleus is known as Duplication.
In a diploid organism, presence of a chromosome
segment in more than two copies per nucleus is
called duplication.
Four types of duplication:
1. Tandem duplication
2. Reverse tandem duplication
3. Displaced duplication
4. Translocation duplication
8
9. The extra chromosome segment
may be located immediately after
the normal segment in precisely
the same orientation forms the
tandem .
When the gene sequence in the
extra segment of a tandem in the
reverse order i.e, inverted , it is
known as reverse tandem
duplication.
In some cases, the extra segment
may be located either on the
same chromosome or on a
different one but away from the
normal segment –termed as
displaced duplication.
Later condition is also termed as
translocation duplication. 9
10. ORIGIN
Origin of duplication involves
chromosome breakage and
reunion of chromosome segment
with its homologous chromosome.
As a result, one of the two
homologous involved in the
production of a duplication ends
up with a deficiency, while the
other has a duplication for the
concerned segment.
Another phenomenon, known as
unequal crossing over, also leads
to exactly the same consequences
for small chromosome segments.
For e.g., duplication of the band
16A of X chromosome of
Drosophila produces Bar eye.
This duplication is believed to
originate due to unequal crossing
over between the two normal X
chromosomes of female. 10
11. GENETIC EFFECTS
Majority of small duplications have no phenotypic effect
However, they provide raw material for evolutionary change
Lead to the formation of gene families.
A gene family consists of two or more genes that are
similar to each other derived from a common gene
ancestor ex- globin gene family whose Genes encode
proteins that bind oxygen
Tandem duplications play a major role in evolution, because
it is easy to generate extra copies of the duplicated genes
through the process of unequal crossing over. These extra
copies can then mutate to take on altered roles in the cell, or
they can become pseudogenes, inactive forms of the gene, by
mutation. 11
12. INVERSION
• When a segment of chromosome is oriented in the reverse
direction, such segment said to be inverted and the phenomenon
is termed as inversion.
• The existence of inversion was first detected by Strutevant and
Plunkett in 1926.
• Inversion occur when parts of chromosomes become detached ,
turn through 1800 and are reinserted in such a way that the genes
are in reversed order.
• For example, a certain segment may be broken in two places,
and the breaks may be in close proximity because of chance loop
in the chromosome.
• When they rejoin, the wrong ends may become connected.
• The part on one side of the loop connects with broken end
different from the one with which it was formerly connected.
• This leaves the other two broken ends to become attached.
• The part within the loop thus becomes turned around or invert
12
13. Inversion may be classified into two types:
PERICENTRIC - include the centromere
PARACENTRIC - do not include the centromere
13
14. Individuals with one copy of a normal chromosome and one copy of an inverted
chromosome
Usually phenotypically normal
Have a high probability of producing gametes that are abnormal in genetic
content
Abnormality due to crossing-over within the inversion interval
During meiosis I, homologous chromosomes synapse with each other
For the normal and inversion chromosome to synapse properly, an inversion
loop must form
If a cross-over occurs within the inversion loop, highly abnormal
chromosomes are produced
Inversions in natural populations
In natural populations, pericentric inversions are much less frequent than
paracentric inversions.
In many sp, however, pericentric inversions are relatively common, e.g., in
some Drosophila. Grasshoppers etc.
Paracentric inversions appear to be very frequent in natural populations of
Zea maize etc.
INVERSION HETEROZYGOTES
14
15. When a paracentric inversion crosses
over with a normal chromosome, the
resulting chromosomes are an acentric, with
no centromeres, and a dicentric, with 2
centromeres.
The acentric chromosome isn't attached to
the spindle, so it gets lost during cell
division, and the dicentric is usually pulled
apart (broken) by the spindle pulling the two
centromeres in opposite directions. These
conditions are lethal.
Eg, Dicentric bridges formed in Maize
female tissue and pollen grains are sterile. 15
16. Crossing Over Within Inversion Interval
Generates Unequal Sets of Chromatids
PARACENTRIC INVERSION
16
17. When a pericentric inversion crosses over
with a normal chromosome, the resulting
chromosomes are both duplicated for some
genes and deleted for other genes. (They do
have 1 centromere apiece though). The gametes
resulting from these are aneuploid and do not
survive. Eg, Drosophila.
Thus, either kind of inversion has lethal
results when it crosses over with a normal
chromosome. The only offspring that survive
are those that didn't have a crossover. Thus
when you count the offspring you only see the
non-crossovers, so it appears that crossing over
has been suppressed. 17
18. Crossing Over Within Inversion Interval
Generates Unequal Sets of Chromatids
PERICENTRIC INVERSION
18
19. Inversions Prevent Generation of Recombinant
Offspring Genotypes
• Only parental chromosomes (non-
recombinants) will produce normal progeny
after fertilization
PARACENTRICPERICENTRIC 19
20. TRANSLOCATION
Integration of a chromosome segment into a nonhomologous
chromosome is known as translocation.
Three types:
1. simple translocation
2. shift
3. reciprocal translocation.
1. Simple translocation: In this case, terminal segment of a
chromosome is integrated at one end of a non-homologous
region. Simple translocations are rather rare.
2. Shift: In shift, an intercalary segment of a chromosome is
integrated within a non-homologous chromosome. Such
translocations are known in the populations of
Drosophila, Neurospora etc.
3. Reciprocal translocation: It is produced when two non-
homologous chromosomes exchange segments – i.e., segments
reciprocally transferred. Translocation of this type is most
common eg, Rhoeo, Oenothera, Tradescantia etc. 20
22. In reciprocal translocations two non-homologous
chromosomes exchange genetic material
Usually generate so-called balanced translocations
Usually without phenotypic consequences
Although can result in position effect.
CYTOLOGY OF TRANSLOCATION HETEROZYGOTE
In simple translocations the transfer of genetic material
occurs in only one direction
These are also called unbalanced translocations
Unbalanced translocations are associated with phenotypic
abnormalities or even lethality
Example: Familial Down Syndrome
In this condition, the majority of chromosome 21 is attached to
chromosome 14. 22
23. Individuals carrying balanced translocations have
a greater risk of producing gametes with
unbalanced combinations of chromosomes.
This depends on the segregation pattern during
meiosis I
During meiosis I, homologous chromosomes
synapse with each other
For the translocated chromosome to synapse
properly, a translocation cross must form
Balanced Translocations and Gamete Production
BALANCED LETHALS AND GAMETIC
COMPLEXES
23
24. Meiotic segregation can occur in one of three ways
1. Alternate segregation
Chromosomes on opposite sides of the translocation cross
segregate into the same cell
Leads to balanced gametes
Both contain a complete set of genes and are thus viable
2. Adjacent-1 segregation
Adjacent non-homologous chromosomes segregate into the
same cell
Leads to unbalanced gametes
Both have duplications and deletions and are thus inviable
3. Adjacent-2 segregation
Adjacent homologous chromosomes segregate into the same
cell
Leads to unbalanced gametes
Both have duplications and deletions and are thus inviable24