Meiosis is a cell division process that produces gametes (sex cells) with half the number of chromosomes. During meiosis, homologous chromosomes pair up and may exchange DNA segments through a process called crossing over. Crossing over increases genetic diversity and helps ensure balanced distribution of chromosomes in gametes. It occurs during prophase I through the formation of chiasmata between nonsister chromatids. Crossing over plays an important role in evolution by allowing independent assortment of genetic variants on chromosomes.
This Power Point Presentation is designed to explain Mendel's experiment on hybridization and dihybrid cross which considers inheritance of two traits at a time and to know whether they are inherited independently or are influenced by each other and also about Law of Independent assortment
This Power Point Presentation is designed to explain Mendel's experiment on hybridization and dihybrid cross which considers inheritance of two traits at a time and to know whether they are inherited independently or are influenced by each other and also about Law of Independent assortment
Cytoplasmic inheritance and extra chromosomal inheritanceJs Mn
the cytoplasmic inheritance is in which cytoplasm contain self replicating hereditary material of cytoplasm formed of DNA and this DNA govern many specific characters in plants and animals.
Cell cell hybridization or somatic cell hybridizationSubhradeep sarkar
What is Cell-Cell Hybridization?
History
More about Somatic cell Hybridization
Mapping of genes by somatic cell Hybridization
Hybridoma technology
Other Applications of Somatic Cell Hybridization
Examples of Codominance. The best example, in this case, is the codominance blood type. ABO group is considered to be a codominant blood group where both father’s and mother’s blood group is expressed. It means that the properties of the blood groups exist in the ABO type.
Codominance is a relationship between two versions of a gene. Individuals receive one version of a gene, called an allele, from each parent. If the alleles are different, the dominant allele usually will be expressed, while the effect of the other allele, called recessive, is masked.
A complementation test (sometimes called a "cis-trans" test) can be used to test whether the mutations in two strains are in different genes. By taking an example of Benzer's work, complementation has been explained.
Cytoplasmic inheritance and extra chromosomal inheritanceJs Mn
the cytoplasmic inheritance is in which cytoplasm contain self replicating hereditary material of cytoplasm formed of DNA and this DNA govern many specific characters in plants and animals.
Cell cell hybridization or somatic cell hybridizationSubhradeep sarkar
What is Cell-Cell Hybridization?
History
More about Somatic cell Hybridization
Mapping of genes by somatic cell Hybridization
Hybridoma technology
Other Applications of Somatic Cell Hybridization
Examples of Codominance. The best example, in this case, is the codominance blood type. ABO group is considered to be a codominant blood group where both father’s and mother’s blood group is expressed. It means that the properties of the blood groups exist in the ABO type.
Codominance is a relationship between two versions of a gene. Individuals receive one version of a gene, called an allele, from each parent. If the alleles are different, the dominant allele usually will be expressed, while the effect of the other allele, called recessive, is masked.
A complementation test (sometimes called a "cis-trans" test) can be used to test whether the mutations in two strains are in different genes. By taking an example of Benzer's work, complementation has been explained.
Linkage
Genes far apart on the same assort independently are not linked
The position of the gene – locus
Occurs in the prophase of meiosis 1 where homologous chromosomes break at identical locations and rejoin with each other
Two genes are said to be under linkage, or linked, when they are located on the same chromosome.
Example: peas T=tall; t=short R=red; r=white
Crossing Over
Crossing over is a recombination of genes due to exchange of genetic material between two homologous chromosomes
It is the mutual exchange of segments of genetic material between non-sister chromatids of two homologous chromosomes, so as to produce re-combinations or new combinations of genes.
It occurs in the pachytene stage, at four strand stage with the help of enzymes (endonuclease, exo-nuclease, R-protein or recombinase;
Stern and Hotta,(1969, 1978).
There is breakage of chromatid segments, exchange of nonsister chromatid segments and later their fusion in new places.
How to Make Awesome SlideShares: Tips & TricksSlideShare
Turbocharge your online presence with SlideShare. We provide the best tips and tricks for succeeding on SlideShare. Get ideas for what to upload, tips for designing your deck and more.
Introduction, Types-somatic and germinal; Mechanism of meiotic crossing oversynapsis, duplication of chromosomes, breakage and union, terminalization;
Cytological basis of crossing over - Stern’s experiment in Drosophila; Creighton
and McClintock’s experiment in Maize; Crossing over in Drosophila, Construction
of genetic maps in Drosophila - two point and three-point crosses; Interference and
coincidence.
Biology Mitosis Lab
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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.
THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.Sérgio Sacani
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.
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.
Cancer cell metabolism: special Reference to Lactate PathwayAADYARAJPANDEY1
Normal Cell Metabolism:
Cellular respiration describes the series of steps that cells use to break down sugar and other chemicals to get the energy we need to function.
Energy is stored in the bonds of glucose and when glucose is broken down, much of that energy is released.
Cell utilize energy in the form of ATP.
The first step of respiration is called glycolysis. In a series of steps, glycolysis breaks glucose into two smaller molecules - a chemical called pyruvate. A small amount of ATP is formed during this process.
Most healthy cells continue the breakdown in a second process, called the Kreb's cycle. The Kreb's cycle allows cells to “burn” the pyruvates made in glycolysis to get more ATP.
The last step in the breakdown of glucose is called oxidative phosphorylation (Ox-Phos).
It takes place in specialized cell structures called mitochondria. This process produces a large amount of ATP. Importantly, cells need oxygen to complete oxidative phosphorylation.
If a cell completes only glycolysis, only 2 molecules of ATP are made per glucose. However, if the cell completes the entire respiration process (glycolysis - Kreb's - oxidative phosphorylation), about 36 molecules of ATP are created, giving it much more energy to use.
IN CANCER CELL:
Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
This results in only 2 molecules of ATP per each glucose molecule instead of the 36 or so ATPs healthy cells gain. As a result, cancer cells need to use a lot more sugar molecules to get enough energy to survive.
Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
This results in only 2 molecules of ATP per each glucose molecule instead of the 36 or so ATPs healthy cells gain. As a result, cancer cells need to use a lot more sugar molecules to get enough energy to survive.
introduction to WARBERG PHENOMENA:
WARBURG EFFECT Usually, cancer cells are highly glycolytic (glucose addiction) and take up more glucose than do normal cells from outside.
Otto Heinrich Warburg (; 8 October 1883 – 1 August 1970) In 1931 was awarded the Nobel Prize in Physiology for his "discovery of the nature and mode of action of the respiratory enzyme.
WARNBURG EFFECT : cancer cells under aerobic (well-oxygenated) conditions to metabolize glucose to lactate (aerobic glycolysis) is known as the Warburg effect. Warburg made the observation that tumor slices consume glucose and secrete lactate at a higher rate than normal tissues.
This pdf is about the Schizophrenia.
For more details visit on YouTube; @SELF-EXPLANATORY;
https://www.youtube.com/channel/UCAiarMZDNhe1A3Rnpr_WkzA/videos
Thanks...!
A brief information about the SCOP protein database used in bioinformatics.
The Structural Classification of Proteins (SCOP) database is a comprehensive and authoritative resource for the structural and evolutionary relationships of proteins. It provides a detailed and curated classification of protein structures, grouping them into families, superfamilies, and folds based on their structural and sequence similarities.
Slide 1: Title Slide
Extrachromosomal Inheritance
Slide 2: Introduction to Extrachromosomal Inheritance
Definition: Extrachromosomal inheritance refers to the transmission of genetic material that is not found within the nucleus.
Key Components: Involves genes located in mitochondria, chloroplasts, and plasmids.
Slide 3: Mitochondrial Inheritance
Mitochondria: Organelles responsible for energy production.
Mitochondrial DNA (mtDNA): Circular DNA molecule found in mitochondria.
Inheritance Pattern: Maternally inherited, meaning it is passed from mothers to all their offspring.
Diseases: Examples include Leber’s hereditary optic neuropathy (LHON) and mitochondrial myopathy.
Slide 4: Chloroplast Inheritance
Chloroplasts: Organelles responsible for photosynthesis in plants.
Chloroplast DNA (cpDNA): Circular DNA molecule found in chloroplasts.
Inheritance Pattern: Often maternally inherited in most plants, but can vary in some species.
Examples: Variegation in plants, where leaf color patterns are determined by chloroplast DNA.
Slide 5: Plasmid Inheritance
Plasmids: Small, circular DNA molecules found in bacteria and some eukaryotes.
Features: Can carry antibiotic resistance genes and can be transferred between cells through processes like conjugation.
Significance: Important in biotechnology for gene cloning and genetic engineering.
Slide 6: Mechanisms of Extrachromosomal Inheritance
Non-Mendelian Patterns: Do not follow Mendel’s laws of inheritance.
Cytoplasmic Segregation: During cell division, organelles like mitochondria and chloroplasts are randomly distributed to daughter cells.
Heteroplasmy: Presence of more than one type of organellar genome within a cell, leading to variation in expression.
Slide 7: Examples of Extrachromosomal Inheritance
Four O’clock Plant (Mirabilis jalapa): Shows variegated leaves due to different cpDNA in leaf cells.
Petite Mutants in Yeast: Result from mutations in mitochondrial DNA affecting respiration.
Slide 8: Importance of Extrachromosomal Inheritance
Evolution: Provides insight into the evolution of eukaryotic cells.
Medicine: Understanding mitochondrial inheritance helps in diagnosing and treating mitochondrial diseases.
Agriculture: Chloroplast inheritance can be used in plant breeding and genetic modification.
Slide 9: Recent Research and Advances
Gene Editing: Techniques like CRISPR-Cas9 are being used to edit mitochondrial and chloroplast DNA.
Therapies: Development of mitochondrial replacement therapy (MRT) for preventing mitochondrial diseases.
Slide 10: Conclusion
Summary: Extrachromosomal inheritance involves the transmission of genetic material outside the nucleus and plays a crucial role in genetics, medicine, and biotechnology.
Future Directions: Continued research and technological advancements hold promise for new treatments and applications.
Slide 11: Questions and Discussion
Invite Audience: Open the floor for any questions or further discussion on the topic.
Richard's entangled aventures in wonderlandRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
2. What is Meiosis?
• Meiosis is a process where a single cell divides
twice to produce four cells containing half the
original amount of genetic information. These cells
are our sex cells – sperm in males, eggs in females.
• Meiosis can be divided into nine stages. These are
divided between the first time the cell divides
(meiosis I) and the second time it divides (meiosis
II).
3.
4. We Are UNIQUE!
• One of the reasons for this genetic mix up or
uniqueness is by a process called Crossing Over
that occurs during meiosis.
5. What is Crossing over?
• Crossing over is the exchange of segments between the
non-sister chromatids of homologous chromosome.
• The term crossing over was coined by Morgan.
6. Origins:
There are two popular and overlapping theories
explaining the origins of crossing-over, coming from
the different theories on the origin of meiosis.
1. The first theory rests upon the idea that meiosis evolved as
another method of DNA repair, and thus crossing-over is a
novel way to replace possibly damaged sections of DNA.
2. The second theory comes from the idea that meiosis
evolved from bacterial transformation, with the function of
propagating diversity.
7. Mechanism of meiotic crossing
over.
The major steps in meiotic crossing over are
1 ) synapsis
2) duplication of chromosome
3) crossing over and
4) terminalisation.
8. -Synapsis is the intimate pairing between the two
homologous chromosomes.
-Synapsis is followed by duplication of chromosome (in
pachytene).
-Crossing over or exchange of segments between the non-
sister chromatids of homologous chromosome occurs at
the tetrad stage.
-Crossing over can be divided into three major steps:
1 ) breakage of chromatid segments
2) their transposition (movement to the respective site)
3) fusion or joining.
9. The final step is terminalisation. After crossing over the
non-sister chromatids starts to repel each
other.
Chiasma itself moves in a zipper fashion towards the end
of tetrad. This movement of chiasma is known as
terminalisation.
10. The Biology Underlying Mendelian Inheritance
• Mendel’s Laws can be derived directly from our understanding of Meiotic
cell division or Meiosis.
• The purpose of meiosis is to introduce further genetic diversity by creating
gametes, either egg
cells or sperm cells, that are genetically different from the parent cells.
11. What is the function of crossing-over?
• In species that reproduce sexually, offspring are genetically distinct
from their parents because they inherit genetic material from
both.
• Such genetic diversity is the product of meiosis, a type of cellular
division that creates reproductive cells from a parent cell.
• The paired chromosomes can exchange segments of DNA via a
mechanism called crossing-over.
12. Crossing-over has two main functions.
1. The first is to increase genetic recombination.
2. The second is to ensure that parental chromosomes are equitably distributed
among the reproductive cells produced by meiosis.
• Without crossing-over, the chromosomes would be distributed abruptly.
• Too many crossing over is also not good because could disrupt advantageous
gene combinations that have established themselves over evolutionary time.
13. Crossing over in favor of plant breeding.
• Increasing the number of crossing-over events could
lead to more genetic recombination and thus
novel gene combinations, a desirable outcome in the
context of plant breeding.
• Ex- Arabidopsis thaliana
Increasing genetic recombination by inhibiting
mechanisms that limit crossing-over.
14. Mechanism of Crossing Over:
• It occurs during Prophase I of Meiosis
• Genetic swapping occurs between paired homologous
chromosomes in our sex cells—The Egg and Sperm
Homologous Chromosomes Exchanging DNA
by Crossing Over
From: http://www.ultranet.com/~jkimball/BiologyPages/M/Meiosis.html#crossing_over
15. Its Why You and I Don’t Look
Alike
Crossing Over ensures a
combination of the maternal and
paternal genes we inherited
BOTTOM LINE
16. • So, when chromosomes separated during meiosis II,
some of the daughter cell receive daughter chromosome
with recombined alleles.
• Due to this genetic recombination offspring have a
different set of genes and alleles than there parents
17. Crossing over and Chiasmata
• Chiasmata is the point where two homologous non-
sister chromatids exchange genetic material during
crossing over during meiosis.
• Chiasmata becomes visible during diplotene stage
of prophase I during meiosis.
• But actual crossing over occcur during previous
pachytene stage. When each tetrad which is
composed of two pairs of sister chromatids begins
to split. Only point of contact is chaismata.
19. Types of Crossing over
• Single crossing over:
Chromosomal crossover (or crossing over) is the
exchange of genetic material between homologous
chromosomes that results in recombinant
chromosomes. It is one of the final phases of genetic
recombination, which occurs during prophase I of
meiosis (pachytene) during a process called synapsis.
21. Double crossing over
It refers to formation of two chiasmata between non-sister chromatids of
homologous chromosomes.
Two simultaneous reciprocal breakage and reunion events between the same two
chromatids.
22. The biological significance of meiosis.
1. The conventional view that it generates by recombination
and sexual reproduction the genetic diversity on which
natural selection can act.
2. That recombination at meiosis plays an important role in the
repair of genetic defects in germ line cells.
3. That it is essential, at least in animals, for the reprogramming
of gametes which give rise to the fertilized egg.
4. That it helps maintain the immortality of the germ line
23. Significance of crossing over
• Crossing over is universal in occurrence, occurs in plants,
animals, bacteria, viruses and moulds.
• Meiotic crossing over allows a more independent selection
between the two alleles that occupy the positions of
single genes, as recombination shuffles the allele content
between sister chromatids
• Helps in proving linear arrangement of genes.
• Recombination does not have any influence on
the statistical probability that another offspring will have
the same combination. This theory of “independent
assortment” of alleles is fundamental to
genetic inheritance.
• Origin of new character.
• Necessary for natural selection, as it increases chances
of variation.
• Ex-Selection of useful recombination by geneticists has brought about green
revolution in our country.
24. Role of Crossing over in Evolution
• Crossing over allows genetic variants on the same chromosome to evolve
independently, which greatly increases an organism's evolutionary potential.
• (Explanation)
• If there were no crossing over, all genetic variants on a chromosome would be inherited
as a block. Image a chromosome copy which contains a good variant--let's say, flu
resistance--at one gene, and a bad variant--let's say, tapeworm susceptibility--at a
different gene. Without crossing over, the population has to choose between flu and
tapeworms. Crossing over can produce a chromosome with the good variant and
without the bad one, allowing the population to move toward a better solution. This
speeds up the rate of adaptation.
This process is requiredto produce egg and sperm cells for sexual reproduction. During reproduction,when the sperm and egg unite to form a single cell, the number ofchromosomes is restored in the offspring
For 4th pt possible by a process of rejuvenation involving the removal of faulty RNA and protein molecules, or by the elimination of defective meiocytes.
The removal of epigenetic defects by recombination during meiosis therefore becomes an essential part of a reprogramming and rejuvenation process.
Assuming some epigenetic defects are nevertheless transmitted to the next generation, sexual reproduction and outbreeding would be advantageous because they provide the opportunity for their removal at the next meiosis. Inbreeding would be disadvantageous, because it increases the probability that epigenetic defects would become homozygous and could no longer be removed by recombination.