Variation-Genetic variation is the difference in DNA sequences between individuals within a population. Variation occurs in germ cells i.e. sperm and egg, and also in somatic (all other) cells. Only variation that arises in germ cells can be inherited from one individual to another and so affect population dynamics, and ultimately evolution.
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.
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.
Speciation is the evolutionary process by which reproductively isolated biological populations evolve to become distinct species.There are few mechanisms through which this process can be well understood.
KEY POINTS
Evolution is a slow and gradual STEP BY STEP process.
Irreversible transformations takes place from simple to complex or advanced occurring in time and space.
Darwin assumed that if evolution is gradual , then there should be a record in fossils of small incremental change within a species. But in many cases, Darwin, and scientists today, are unable to find most of these intermediate forms.
Mutation, genetic drift, gene flow, non-random mating, and natural selection are the 5 key mechanisms responsible for evolution.
Variation, inheritance, selection and time are the 4 principles that are considered as the components of the evolutionary mechanism of natural selection.
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.
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.
Speciation is the evolutionary process by which reproductively isolated biological populations evolve to become distinct species.There are few mechanisms through which this process can be well understood.
KEY POINTS
Evolution is a slow and gradual STEP BY STEP process.
Irreversible transformations takes place from simple to complex or advanced occurring in time and space.
Darwin assumed that if evolution is gradual , then there should be a record in fossils of small incremental change within a species. But in many cases, Darwin, and scientists today, are unable to find most of these intermediate forms.
Mutation, genetic drift, gene flow, non-random mating, and natural selection are the 5 key mechanisms responsible for evolution.
Variation, inheritance, selection and time are the 4 principles that are considered as the components of the evolutionary mechanism of natural selection.
Chromosomal Variations, Continuous and Discontinuous Variations, Genotypic & ...Muhammad Mubashir Ali
Chromosomal Variations, Continuous and Discontinuous Variations, Genotypic & Phenotypic Variations. Hardy-Weinberg law of random mating, Recombination technology
It also explains the main points for a variation.
This is PPT on Evolution. This is just and introductory PPT. Soon There will be a PPT with much more on Evolution. Hope That you all like it. please like and share. each like Counts.
edexcel gcse core science, biology one (B1)jubbi01
detailed notes on each chapter of biology one, core science exam board edexcel.
includes visually engaging elements and useful relevant information.
-science
-core science
-biology
-gcse
-edexcel
The following power point presentation discusses about the concepts of Heridity and Evolution. In it, we discuss the laws of Heridity given by Mendel. We also see how Mendel was able to infer and analyze the results he obtained. There after, we study about the structure and function of chromosomes, genes and DNA. Then we discuss about the concept of Evolution, how Evolution resulted in formation of species, we discuss the various theories of Evolution and we track the path of evolution using various references we observe in the living world
Hear Duke evolutionary biologist Mohamed Noor discuss the work that made him one of only a dozen scientists honored with the Darwin-Wallace Medal in 2008. This prize is given only once every fifty years to those twelve scientists who have done the most to advance Darwin's thinking.
Although Darwin's book title suggested that he provided us with insights on the origin of species, in fact, he only focused on the process of divergence within species and assumed the same process "eventually" led to something that could be called a new species.
This event was taped live as part of the Periodic Tables: Durham's Science Cafe series at the Broad Street Cafe. Periodic Tables is a Museum of Life and Science program. For more info please visit us at http://www.ncmls.org/periodictables
Evolution on how Charles Darwin the father of evolution explained the different types of mechanisms of evolution these are by natural selection, genetic drift, gene flow and many more
The isolation, culture and fusion of protoplasts is a fascinating field in plant research. Protoplast isolation and their cultures provide millions of single cells (comparable to microbial cells) for a variety of studies.
Protein targeting or protein sorting is the biological mechanism by which proteins are transported to their appropriate destinations in the cell or outside it. Proteins can be targeted to the inner space of an organelle, different intracellular membranes, plasma membrane, or to exterior of the cell via secretion.
Protein Folding-biophysical and cellular aspects, protein denaturationAnishaMukherjee5
Protein folding is the physical process by which a protein chain acquires its native 3-dimensional structure, a conformation that is usually biologically functional, in an expeditious and reproducible manner.
Seminar of U.V. Spectroscopy by SAMIR PANDASAMIR PANDA
Spectroscopy is a branch of science dealing the study of interaction of electromagnetic radiation with matter.
Ultraviolet-visible spectroscopy refers to absorption spectroscopy or reflect spectroscopy in the UV-VIS spectral region.
Ultraviolet-visible spectroscopy is an analytical method that can measure the amount of light received by the analyte.
(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.
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.
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.
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 aventures in two entangled wonderlandsRichard 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.
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.
2. CONTENTS
INTRODUCTION
DEFINITION OF VARIATION
NATURE OF VARIATIONS
TYPES OF VARIATIONS
SOURCES OF VARIATIONS
GENE MUTATION
CHROMOSOMAL ABERRATIONS
RECOMBINATION
HYBRIDIZATION
ISOLATION
NATURAL SELECTION
SEXUAL SELECTION
REFERENCES
3. INTRODUCTION
The behaviour shown by each and every
individual organism is different from each
other.
Every organism in the universe show
variation among themselves.
Even the identical twins of the same parents
differ in some or more aspects.
A morphological or a physiological change
in organisms due to either genetic or
environmental reasons is said to be
variation.
4. DEFINITION OF VARIATION
The differences between the closely related
organisms occurring in the same environment
are called variations.
Example:- skin colour, hair colour ,dimples
,height, odour etc
5. NATURE OF VARIATIONS
Variations may influence any character of the
individuals .These may be :-
MORPHOLOGICAL VARIATIONS-These are seen
in shape,size,colour or pattern of body parts of the
organisms.
PHYSIOLOGICAL VARIATIONS- Theses affect the
physiological processes and functioning of organs.
ECOLOGICAL VARIATIONS- These are produced
by the influence of environment & are usually non-
heritable.
PSYCHOLOGICAL VARIATIONS- These include
changes in the mental health.
6. The morphological or physiological differences may arise
either because of genetic changes among the individuals or
because of environmental influence or maybe the result of
both. These may be:
HERITABLE VARIATIONS(GENETIC VARIATIONS)-
These arise due to changes in the genetic material & are
passed onto the next generation.
These variations have evolutionary significance.
NON-HERITABLE VARIATIONS- Such variations are
acquired by the organisms during their lifetime due to the
influence of environment. These are lost with the death of the
organism.
These variations do not have evolutionary significance.
7. TYPES OF VARIATIONS
Variations are of following types :-
MERISTIC VARIATIONS-
It includes the variation in the number of parts of
an organism.
E.g. :- occurrence of 6 digits in hand or foot instead
of normal 5,13 ribs in man instead of 12.
SUBSTANTIVE VARIATION-
It includes variation in shape , size, form or colour
of an organism or its parts.
E.g. :- eye colour, hair
colour, shape of nose, ear, eye,
etc
8. CONTINUOUS VARIATIONS- The
continuous variations are minute variations,
which occur in graded series.
Darwin called them as fluctuations &
described them to be significant for the
evolution and origin of species.
E.g. :- changes in height, colour & odour
9. DISCONTINUOUS VARIATIONS- The
discontinuous variations are sudden & large,
without any intermediate stages.
Darwin termed the large changes as
saltations & believed that they are useless
for evolution.
E.g. :- Harelip in man, presence of 6 fingers
or toes in man, etc.
10. DETERMINATE VARIATIONS - These are
confined to some specific lines & occur in a
specific direction of adaptations.
E.g. :- gradual decrease in the number of
digits in the evolution of horse.
INDETERMINATE VARIATIONS – Variation
which are not governed by any law but take
place in some imaginary or thinkable
direction of change. These may be called
fluctuating variations.
11. SOMATIC / SOMATOGENIC / ACQUIRED / NON-
HERITABLE VARIATIONS -
Characters which appears on the somatic cells are
called somatic variations.
These are not heritable & are lost with the death of
person.
E.g. :- better developed muscles of athletes , small
feet of Chinese ladies , etc.
GERMINAL / CONSTIUTIONAL / CONGENITAL
VARIATIONS -
Characters appearing in the germ cells of an organism
are called germinal variations.
These are heritable & are transferred to the offspring.
E.g. :- Occurrence of supernumerary digits in man ,
horse , cat , etc.
12. SOURCES OF VARIATION
The sources of somatic & blastogenic
variations are different.
Somatogenic variations are caused by
environmental factors such as heat or cold,
scarcity of food, etc.
The blastogenic variations are produced by
genetic variability.
13. The various causes of variations are as follows :-
GENE MUTATION -
Spontaneous change in a gene is called gene
mutation.
As this change occurs in a particular locus of the
chromosome, it is called point mutation.
During cell division, when the chromosomes divides,
the gene also produces exact copies of their own.
But once in a while, a gene may not produce its own
copy, but a different one.
This change is mutation & the changed gene is
called mutant.
The mutation produces a different phenotypic
character. Thus mutation produces variations.
14. CHROMOSOMAL ABERRATIONS -
The chromosome of each species has a
characteristic structure and number.
But due to certain accidents or irregularities
at the time of cell division, crossing over or
fertilization some alterations in the
morphology & number takes place which is
called chromosomal aberrations.
It affects the phenotypic characters. Thus
variation is produced by chromosomal
aberrations.
16. RECOMBINATION
The formation of the gene combination not present in
the parental type is called recombination.
Recombination is a process of mixing & reshuffling of
the genes of the chromosomes of their parents.
In sexually reproducing organisms, during gamete
formation the two sets of genes segregate in a
manner which results in haploid gametes.
When the gametes of two parents unites during
fertilization, the two sets of genes pair again.
During the process of gamete formation & fertilization,
a great array of recombination of pairs of genes
occurs because of segregation, independent
assortment and crossing over.
Recombination is a primary source of variation.
17. HYBRIDIZATION
Hybridization is the interbreeding or crossing
between the individuals of two different species
so that the genes from one species are
introduced into the gene pool of another
species.
It brings together genes from two different gene
pools.
TYPES OF HYBRIDIZATION :-
INTERSPECIFIC HYBRIDIZATION- It is the crossing
between two different species of the same
genera.
INTERGENERIC HYBRIDIZATION- It is the crossing
18. SALIENT FEATURES OF HYBRIDIZATION :-
It brings two different genes together.
It increases the size of gene pool.
It brings about new combination of genes.
It establishes variations in the population.
It leads to formation of new varieties & species.
LIMITATIONS OF HYBRIDIZATION :-
The hybrids are usually sterile, only a few are
fertile.
New combinations of genes need to be stabilized
in the population.
New environmental niches are needed for new
hybrids.
19. ISOLATION
Isolation is the separation of individuals of a
species by some barrier, which prevents
interbreeding.
Isolation is of two types :-
GEOGRAPHICAL ISOLATION- It is caused by
agents like water body, land, desert,
mountains, river, etc.
REPRODUCTIVE ISOLATION- It is caused by
genetically determined factors.
20. NATURAL SELECTION
Natural selection is the process whereby
organisms better adapted to their
environment tend to survive & produce more
offspring.
It is the differential survival & reproduction of
individuals due to differences in phenotype.
It is a key mechanism of evolution.
21. SEXUAL SELECTION
It is a mode of natural selection where
members of one biological sex choose
members of the other sex to mate with
(intersexual selection).
They compete with the members of same
sex for access to members of opposite sex.
(intrasexual selection).
