Inversions involve breaks in a chromosome where a segment rotates 180 degrees and rejoins at the breakpoints. There are two main types of inversions - single and complex. A single inversion involves one inverted segment, which can be paracentric where breaks are in the same arm, or pericentric where breaks are in different arms and may include the centromere. Complex inversions have more than one inverted segment. Inversions can affect fertility through unbalanced gametes, cause recessive mutations, and influence gene expression through position effects. They may also play a role in evolution by allowing populations to diverge.
Chromosomes are known as hereditary vehicles
They are formed of strands of DNA molecules which contain information for the development of different characteristics and performance of various metabolic activities of the cells
The coordination of various function is brought about through the formation of enzymes which are complex protein molecules
Inheritance due to genes located in cytoplasm is called cytoplasmic inheritance.
Since genes governing traits showing cytoplasmic inheritance are located outside the nucleus and in the cytoplasm, they are referred to as plasmagenes.
Chromosomes are known as hereditary vehicles
They are formed of strands of DNA molecules which contain information for the development of different characteristics and performance of various metabolic activities of the cells
The coordination of various function is brought about through the formation of enzymes which are complex protein molecules
Inheritance due to genes located in cytoplasm is called cytoplasmic inheritance.
Since genes governing traits showing cytoplasmic inheritance are located outside the nucleus and in the cytoplasm, they are referred to as plasmagenes.
Maternal effects are the influences of a mothers genotype on the phenotype of her offspring. It results from the asymmetric contribution of the female parent to the development of zygotes.
In terms of chromosomal genes, both male and female parents contribute equally to the zygote. The female parent contributes to the zygotes initial cytoplasm and organelles. Sperm rarely contribute anything other than chromosomes. Therefore zygotic development begins within a maternal medium and hence the maternal cytoplasm directly affects zygotic development.
The SPECIAL - GIANT CHROMOSOMES which are very transcriptionally active DNA, where loops of DNA emerging from an apparently continuous chromosomal axis are coated with RNA polymerase.
Comparatively much larger than polytene chromosomes.
Highly significant for scientific analysis especially regarding gene amplification.
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.
GENETICS
CYTOGENETICS
Definition of Linkage, Coupling and Repulsion hypothesis, Linkage group- Drosophila, maize and man, Types of linkage-complete linkage and incomplete linkage, Factors affecting linkage- distance between genes, age, temperature, radiation, sex, chemicals and nutrition, Significance of linkage.
The tendency of two or more genes to stay together (i.e., the co-existence of two or more genes) in the same chromosome during inheritance is known as LINKAGE. The linked genes are present on the same chromosome are said to be SYNTENIC. The linked genes do not show independent assortment.
LINKAGE v/s INDEPENDENT ASSORTMENT
The frequency of linkage or the strength recombination is influenced by several factors (agents).
Maternal effects are the influences of a mothers genotype on the phenotype of her offspring. It results from the asymmetric contribution of the female parent to the development of zygotes.
In terms of chromosomal genes, both male and female parents contribute equally to the zygote. The female parent contributes to the zygotes initial cytoplasm and organelles. Sperm rarely contribute anything other than chromosomes. Therefore zygotic development begins within a maternal medium and hence the maternal cytoplasm directly affects zygotic development.
The SPECIAL - GIANT CHROMOSOMES which are very transcriptionally active DNA, where loops of DNA emerging from an apparently continuous chromosomal axis are coated with RNA polymerase.
Comparatively much larger than polytene chromosomes.
Highly significant for scientific analysis especially regarding gene amplification.
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.
GENETICS
CYTOGENETICS
Definition of Linkage, Coupling and Repulsion hypothesis, Linkage group- Drosophila, maize and man, Types of linkage-complete linkage and incomplete linkage, Factors affecting linkage- distance between genes, age, temperature, radiation, sex, chemicals and nutrition, Significance of linkage.
The tendency of two or more genes to stay together (i.e., the co-existence of two or more genes) in the same chromosome during inheritance is known as LINKAGE. The linked genes are present on the same chromosome are said to be SYNTENIC. The linked genes do not show independent assortment.
LINKAGE v/s INDEPENDENT ASSORTMENT
The frequency of linkage or the strength recombination is influenced by several factors (agents).
A chromosomal disorder, anomaly, aberration, or mutation is a missing, extra, or irregular portion of chromosomal DNA. It can be from a typical number of chromosomes or a structural abnormality in one or more chromosomes. Chromosome mutation was formerly used in a strict sense to mean a change in a chromosomal segment, involving more than one gene. The term "karyotype" refers to the full set of chromosomes from an individual.
The increased availability of biomedical data, particularly in the public domain, offers the opportunity to better understand human health and to develop effective therapeutics for a wide range of unmet medical needs. However, data scientists remain stymied by the fact that data remain hard to find and to productively reuse because data and their metadata i) are wholly inaccessible, ii) are in non-standard or incompatible representations, iii) do not conform to community standards, and iv) have unclear or highly restricted terms and conditions that preclude legitimate reuse. These limitations require a rethink on data can be made machine and AI-ready - the key motivation behind the FAIR Guiding Principles. Concurrently, while recent efforts have explored the use of deep learning to fuse disparate data into predictive models for a wide range of biomedical applications, these models often fail even when the correct answer is already known, and fail to explain individual predictions in terms that data scientists can appreciate. These limitations suggest that new methods to produce practical artificial intelligence are still needed.
In this talk, I will discuss our work in (1) building an integrative knowledge infrastructure to prepare FAIR and "AI-ready" data and services along with (2) neurosymbolic AI methods to improve the quality of predictions and to generate plausible explanations. Attention is given to standards, platforms, and methods to wrangle knowledge into simple, but effective semantic and latent representations, and to make these available into standards-compliant and discoverable interfaces that can be used in model building, validation, and explanation. Our work, and those of others in the field, creates a baseline for building trustworthy and easy to deploy AI models in biomedicine.
Bio
Dr. Michel Dumontier is the Distinguished Professor of Data Science at Maastricht University, founder and executive director of the Institute of Data Science, and co-founder of the FAIR (Findable, Accessible, Interoperable and Reusable) data principles. His research explores socio-technological approaches for responsible discovery science, which includes collaborative multi-modal knowledge graphs, privacy-preserving distributed data mining, and AI methods for drug discovery and personalized medicine. His work is supported through the Dutch National Research Agenda, the Netherlands Organisation for Scientific Research, Horizon Europe, the European Open Science Cloud, the US National Institutes of Health, and a Marie-Curie Innovative Training Network. He is the editor-in-chief for the journal Data Science and is internationally recognized for his contributions in bioinformatics, biomedical informatics, and semantic technologies including ontologies and linked data.
Multi-source connectivity as the driver of solar wind variability in the heli...Sérgio Sacani
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under debate. A key goal of ESA/NASA’s Solar Orbiter mission is to identify
solar wind sources and understand what drives the complexity seen in the
heliosphere. By combining magnetic feld modelling and spectroscopic
techniques with high-resolution observations and measurements, we show
that the solar wind variability detected in situ by Solar Orbiter in March
2022 is driven by spatio-temporal changes in the magnetic connectivity to
multiple sources in the solar atmosphere. The magnetic feld footpoints
connected to the spacecraft moved from the boundaries of a coronal hole
to one active region (12961) and then across to another region (12957). This
is refected in the in situ measurements, which show the transition from fast
to highly Alfvénic then to slow solar wind that is disrupted by the arrival of
a coronal mass ejection. Our results describe solar wind variability at 0.5 au
but are applicable to near-Earth observatories.
Nutraceutical market, scope and growth: Herbal drug technologyLokesh Patil
As consumer awareness of health and wellness rises, the nutraceutical market—which includes goods like functional meals, drinks, and dietary supplements that provide health advantages beyond basic nutrition—is growing significantly. As healthcare expenses rise, the population ages, and people want natural and preventative health solutions more and more, this industry is increasing quickly. Further driving market expansion are product formulation innovations and the use of cutting-edge technology for customized nutrition. With its worldwide reach, the nutraceutical industry is expected to keep growing and provide significant chances for research and investment in a number of categories, including vitamins, minerals, probiotics, and herbal supplements.
Observation of Io’s Resurfacing via Plume Deposition Using Ground-based Adapt...Sérgio Sacani
Since volcanic activity was first discovered on Io from Voyager images in 1979, changes
on Io’s surface have been monitored from both spacecraft and ground-based telescopes.
Here, we present the highest spatial resolution images of Io ever obtained from a groundbased telescope. These images, acquired by the SHARK-VIS instrument on the Large
Binocular Telescope, show evidence of a major resurfacing event on Io’s trailing hemisphere. When compared to the most recent spacecraft images, the SHARK-VIS images
show that a plume deposit from a powerful eruption at Pillan Patera has covered part
of the long-lived Pele plume deposit. Although this type of resurfacing event may be common on Io, few have been detected due to the rarity of spacecraft visits and the previously low spatial resolution available from Earth-based telescopes. The SHARK-VIS instrument ushers in a new era of high resolution imaging of Io’s surface using adaptive
optics at visible wavelengths.
(May 29th, 2024) Advancements in Intravital Microscopy- Insights for Preclini...Scintica Instrumentation
Intravital microscopy (IVM) is a powerful tool utilized to study cellular behavior over time and space in vivo. Much of our understanding of cell biology has been accomplished using various in vitro and ex vivo methods; however, these studies do not necessarily reflect the natural dynamics of biological processes. Unlike traditional cell culture or fixed tissue imaging, IVM allows for the ultra-fast high-resolution imaging of cellular processes over time and space and were studied in its natural environment. Real-time visualization of biological processes in the context of an intact organism helps maintain physiological relevance and provide insights into the progression of disease, response to treatments or developmental processes.
In this webinar we give an overview of advanced applications of the IVM system in preclinical research. IVIM technology is a provider of all-in-one intravital microscopy systems and solutions optimized for in vivo imaging of live animal models at sub-micron resolution. The system’s unique features and user-friendly software enables researchers to probe fast dynamic biological processes such as immune cell tracking, cell-cell interaction as well as vascularization and tumor metastasis with exceptional detail. This webinar will also give an overview of IVM being utilized in drug development, offering a view into the intricate interaction between drugs/nanoparticles and tissues in vivo and allows for the evaluation of therapeutic intervention in a variety of tissues and organs. This interdisciplinary collaboration continues to drive the advancements of novel therapeutic strategies.
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The return of a sample of near-surface atmosphere from Mars would facilitate answers to several first-order science questions surrounding the formation and evolution of the planet. One of the important aspects of terrestrial planet formation in general is the role that primary atmospheres played in influencing the chemistry and structure of the planets and their antecedents. Studies of the martian atmosphere can be used to investigate the role of a primary atmosphere in its history. Atmosphere samples would also inform our understanding of the near-surface chemistry of the planet, and ultimately the prospects for life. High-precision isotopic analyses of constituent gases are needed to address these questions, requiring that the analyses are made on returned samples rather than in situ.
3. Introduction
Inversion involves at least two breaks in a
chromosome; the broken segment rotates 180°
and is then reunited at the two break points.
4. Introduction
First discovered by Sturtevant in 1921 in Drosophila.
Later detected in a wide variety of plant and animal
species.
Studied extensively in different Drosophila species, such as,
D. pseudoobscura, D. persimilis and D. willistoni in their
salivary chromosomes.
D. meridiana, anopheline mosquitoes, Amphibia, and many
grasshopper sp. relatively free of inversions.
Reported in several plant species like maize, barley, broad
bean, Tradescantia etc.
The most common inversion seen in humans is
on chromosome 9, at inv(9)(p12q13).
This inversion is generally considered to have no harmful
effects, but there is some suspicion it could lead to an
increased risk for miscarriage or infertility for some affected
individuals.
5. Types of Inversion
• Based on the number of inverted segments
within a chromosome and the location of the
inversion points with respect of each other, the
inversion may be broadly classified into two
types:
1. Single inversion
2. Complex inversion
6. Single inversion
• In this case, only one segment of the
chromosome is inverted. There are two types
of single inversion:
Paracentric inversion
Pericentric inversion
7. Paracentric inversion
• The inversion is confined to a single arm of the
chromosome, i.e., both the inversion breakpoints are
located in the same arm.
8. Paracentric inversion
• More common.
• In pachytene and salivary chromosomes, an
inversion in a heterozygous condition can be
recognised by the inversion loop.
• Inversion loop is formed when all the portions
of the two chromosome synapse in a
homologous fashion.
• In a meiotic anaphase the common inversion
bridge results when a crossover takes place
within the inverted section.
9. Paracentric inversion
• The frequency of such crossing over depends
upon
The length of the inverted segment
Its location in the chromosome
Crossover characteristics of the individual
• Resulting chromatids abnormal: dicentric and
acrocentric formation.
• Acentric fragment will be lost (no centromere).
• Dicentric bridge is broken.
• These two events will lead to inviability of
gametes.
11. Paracentric inversion
• However, in Drosophila gamete lethality is not
serious.
• This can be explained as:
No crossing over in males
Lack of crossing over within an inversion or
exclusion of dicentric bridge from the egg nucleus
in females.
• Similar conditions has been seen in the
embryo sacs of maize plant only (1981) among
the higher plants.
• When two crossovers are formed within an
inverted segment, the results will depend on
the number of chromatids involved.
12. Paracentric inversion
• Two strand crossing over
will yield four normal
chromatids, two of which
were involved in crossing
over and the other two were
not.
• Three strand crossing over
yields one non-crossover
chromatid, one crossover
chromatid, and one
dicentric bridge with
acentric fragment.
• Four strand crossing over
yields two dicentric
chromatids and two acentric
fragments.
13. Pericentric inversion
The inverted segment includes the centromere, i.e.,
the two breakpoints are located in different arms of
the chromosome.
14. Pericentric inversion
• If the breaks are equidistant from the
centromere, the chromosome would appear
unchanged morphologically.
• At different distances, a shift in the centromere
position would take place.
• Crossing over within a pericentric
chromosome, when heterozygous, produces
characteristic chromatid products.
• A single crossover within the inversion loop
produces the following:
16. Pericentric inversion
• Crossover that would not result in
deletion/duplication chromatids would be the 2-
strand doubles.
• These would have their frequency determined
by the size of inversion loop.
18. Complex inversion
• Occurrence of more than one inversion in a
chromosome is called complex inversion.
• Based on the mutual relationship of the
inverted regions, it may be grouped into the
following five types:
19. Complex inversion
Independent inversions
Inversions occur in different regions of the chromosome
and they are separated from one another by un-inverted
(normal) segment.
20. Complex inversion
Direct tandem inversions
There are two or more inverted segments which are
directly adjacent to each other, i.e., the inverted regions
are not separated by normal regions.
21. Complex inversion
Reversed tandem inversions
The two inverted segments are adjacent to each other but
their positions are mutually interchanged i.e., g. the first
segment lies in place of the second and vice-versa.
22. Complex inversion
Included inversions
One inversion is confined within another inversion,
i.e., a segment within an inverted segment is inverted
again; as a result, the second inverted segment
possesses the normal gene sequence for the
concerned segment.
23. Complex inversion
Overlapping inversions
Such inversions have a common segment, i.e., a part
of an inverted chromosome segment is inverted
again together with an adjacent segment which was
not included in the first inverted segment.
24. Inversions and Evolution
• Centres largely on the Paracentric type.
• In an organism having a large number of
inversions in the same arm and in which the
salivary gland chromosomes can be studied,
their family history, as well as that of the
species, can be reconstructed by using
overlapping inversions.
• Inversions may also be selected in for natural
populations because each chromatin, due to
crossover, tend to become allelically different
compared to the blocks of chromatin due to
random mutations.
25. Inversions and Evolution
• Size of inversion is important; it must not be
too long to affect the allelic sequence, but
should be long enough to accumulate a genetic
variation which is sufficient to accommodate a
differential response to environmental
variations.
• Inversions can probably serve as a centre for
species divergence, given sufficient time to
accumulate genetic variation and formation of
barriers to prevent breeding with the parent
population.
26. Effects of Inversion
• Effect on Fertility
Fertility of inversion heterozygotes is reduced due to
the production of unbalanced gametes which carry
the deficiency-duplication chromatids obtained from
crossing over within the inversion loop. The effect on
fertility varies according to the type of inversion and
the organism carrying it.
• Recessive mutations
Damage to the DNA at the breakpoints may
sometimes result in a recessive mutation. Some of
the mutations may be recessive lethals; such
mutations are also lethal in hemizygous condition.
27. Effects of Inversion
• Position effect
Due to inversion euchromatic segment of a chromosome
may become located in the vicinity of a heterochromatic
region.
In such a condition, the euchromatic region may become
hetero-chromatinized; this would cause the suppression of
gene activity i.e., suppression of transcription of the
euchromatic segment.
Heterochromatinization is variable as a consequence of
which variegated type (V-type) position effects are
produced.
28. Effects of Inversion
• Effect of inversion on the activity of
nucleolar organizer region (NOR) of other
chromosome
Inversion in one chromosome influences the NOR
activity in the other chromosomes.
Viseras and Camacho in 1991 did not find decreased
activity of NOR in L3 does chromosome due to the
presence of a pericentric inversion in the smallest
chromosome (S11 chromosome) of grasshopper
Aiolopusstrepen.
29. References
1. “Variation: Nature and Consequences of
Altered Chromosomal
Structure.” Cytogenetics, by C. P. Swanson,
2nd ed., Prentice Hall of India., 1988.
2. “Changes in Chromosome Structure.”
Genetics, by Monroe W. Strickberger, 2nd
ed., Macmillan, 1976.
3. http://biologydiscussion.com
4. https://images.google.com/
5. https://en.wikipedia.org/wiki/Chromosomal_in
version