Gene interaction can be additive or non-additive. Non-additive gene action includes dominance variance from heterozygote deviations and epistatic variance from gene interactions. A study of okra lines found non-additive gene action for several traits like flowering time and fruit characteristics, while additive gene action governed traits like fruit weight. A maize study found non-additive effects including overdominance controlled traits like height, flowering time, and yield, indicating potential for exploiting heterosis.
It's about for some interactions occurs between two genes and within a gene and how these interactions changed the phenotypic ratios of Mendelian phenotypic ratios.
GENE SEGREGATION & INTEGRATION
A. Law of Segregation
•B. Law of Independent Assortment
•C. Segregation and Assortment in Haploid Organisms
•D. Dominance Relationship
•E. Multiple Alleles
•F. Lethal Genes
It's about for some interactions occurs between two genes and within a gene and how these interactions changed the phenotypic ratios of Mendelian phenotypic ratios.
GENE SEGREGATION & INTEGRATION
A. Law of Segregation
•B. Law of Independent Assortment
•C. Segregation and Assortment in Haploid Organisms
•D. Dominance Relationship
•E. Multiple Alleles
•F. Lethal Genes
The expression of a single character by the interaction of more than one pair of genes is called the Interaction of genes.
Bateson and Punnet proposed factor hypothesis to explain the Interaction of genes.
The genic interaction is of two types, namely
Non-allelic gene interaction.
Allelic gene interaction.
Allelic and Non-allelic interactions : Complete dominance; Incomplete dominance-in Four O'clock plant, Mirabilis jalapa and Snapdragon, Antirrhinum majus ; Co-dominance- MN blood group, AB blood group, Roan coat colour in shorthorn breed of cattle; Inheritance of Comb pattern in Poultry; Epistasis -Dominant - Fruit colour in Summer squash, Recessive - Coat colour in mice; Complementary gene interaction -Purple flower colour in Sweet pea (Lathyrus odoratus)
Basics of Undergraduate/university fellows
Epistasis is a Greek word that means standing over.
BATESON used term epistasis to describe the masking effect in 1909
The term epistasis describes a certain relationship between genes, where an allele of
one gene hides or masks the visible output or phenotype of another gene.
When two different genes which are not alleles, both affect the same character in such
a way that the expression of one masks (inhibits or suppresses) the expression of the
other gene, the phenomenon is said to be epistasis.
The gene that suppresses other gene expression is known as Epistatic gene.
The gene that is suppressed or remain obscure is called Hypostatic gene
The classical phenotypic ratio of 9:3:3:1 F2 ratio becomes modified by epistasis.
Introduction :
Mendel and subsequent workers assumed that a character was governed by a single gene.
But it was later discovered that many characters in almost all the organisms are governed by two or more genes. Such gene affect the development of concerned characters in various ways.
The phenomenon of two or more gene affecting the expression of each other in various ways in the development of a single character of on organism is known as gene interaction.
The expression of a single character by the interaction of more than one pair of genes is called the Interaction of genes.
Bateson and Punnet proposed factor hypothesis to explain the Interaction of genes.
The genic interaction is of two types, namely
Non-allelic gene interaction.
Allelic gene interaction.
Allelic and Non-allelic interactions : Complete dominance; Incomplete dominance-in Four O'clock plant, Mirabilis jalapa and Snapdragon, Antirrhinum majus ; Co-dominance- MN blood group, AB blood group, Roan coat colour in shorthorn breed of cattle; Inheritance of Comb pattern in Poultry; Epistasis -Dominant - Fruit colour in Summer squash, Recessive - Coat colour in mice; Complementary gene interaction -Purple flower colour in Sweet pea (Lathyrus odoratus)
Basics of Undergraduate/university fellows
Epistasis is a Greek word that means standing over.
BATESON used term epistasis to describe the masking effect in 1909
The term epistasis describes a certain relationship between genes, where an allele of
one gene hides or masks the visible output or phenotype of another gene.
When two different genes which are not alleles, both affect the same character in such
a way that the expression of one masks (inhibits or suppresses) the expression of the
other gene, the phenomenon is said to be epistasis.
The gene that suppresses other gene expression is known as Epistatic gene.
The gene that is suppressed or remain obscure is called Hypostatic gene
The classical phenotypic ratio of 9:3:3:1 F2 ratio becomes modified by epistasis.
Introduction :
Mendel and subsequent workers assumed that a character was governed by a single gene.
But it was later discovered that many characters in almost all the organisms are governed by two or more genes. Such gene affect the development of concerned characters in various ways.
The phenomenon of two or more gene affecting the expression of each other in various ways in the development of a single character of on organism is known as gene interaction.
Genetic parameters is an important issue in animal breeding. Parameters that are of interest are heritability, genetic correlation and repeatability, and those are computed as functions of the variance components.
Heritability (h2) refers to the degree of resemblance between relatives i.e. how much the progeny resemble its parents. Heritability (h2) is the most important genetic parameter on which different breeding strategies depend. The knowledge of h2 is a frontline for the formulation of breeding plans on scientifi c lines, which are used for selection of parents for future breeding program. In order to made breeding plans, there is need to know the h2 of different characters (traits). The extent of genetic control is different for different traits. The higher the h2, the greater is the genetic control on the trait, and the more rapidly selection will result in genetic progress. For
highlyheritable traits, differences in breeding values of animals have large effect on performance, and differences in environments have less important effect on performance. The opposite is true for lowly heritable traits. In other words, heritability could increase if genetic variation increases and it might also increase if the environmental variation decreases. As a rule, signifi cant genetic change can be made by selecting for highly heritable traits. For lowly heritable traits, selection is less effective; so performance may be improved through management. Therefore, the aim of this review is to defi ne heritability (h2) and assess its role in animal breeding.
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.
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.
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Functional Magnetic Resonance Imaging (fMRI) provides means to characterize brain activations in response to behavior. However, cognitive neuroscience has been limited to group-level effects referring to the performance of specific tasks. To obtain the functional profile of elementary cognitive mechanisms, the combination of brain responses to many tasks is required. Yet, to date, both structural atlases and parcellation-based activations do not fully account for cognitive function and still present several limitations. Further, they do not adapt overall to individual characteristics. In this talk, I will give an account of deep-behavioral phenotyping strategies, namely data-driven methods in large task-fMRI datasets, to optimize functional brain-data collection and improve inference of effects-of-interest related to mental processes. Key to this approach is the employment of fast multi-functional paradigms rich on features that can be well parametrized and, consequently, facilitate the creation of psycho-physiological constructs to be modelled with imaging data. Particular emphasis will be given to music stimuli when studying high-order cognitive mechanisms, due to their ecological nature and quality to enable complex behavior compounded by discrete entities. I will also discuss how deep-behavioral phenotyping and individualized models applied to neuroimaging data can better account for the subject-specific organization of domain-general cognitive systems in the human brain. Finally, the accumulation of functional brain signatures brings the possibility to clarify relationships among tasks and create a univocal link between brain systems and mental functions through: (1) the development of ontologies proposing an organization of cognitive processes; and (2) brain-network taxonomies describing functional specialization. To this end, tools to improve commensurability in cognitive science are necessary, such as public repositories, ontology-based platforms and automated meta-analysis tools. I will thus discuss some brain-atlasing resources currently under development, and their applicability in cognitive as well as clinical neuroscience.
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.
Seminar of U.V. Spectroscopy by SAMIR PANDASAMIR PANDA
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Ultraviolet-visible spectroscopy is an analytical method that can measure the amount of light received by the analyte.
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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.
1. Gene Interaction: Non additive gene
action
Delivered on: 12/04/2018
Delivered by
Dipti Kujur
M.Sc.(Ag.) Previous Year
Dept. Of Genetics and Plant
Breeding
Presentation on
2. Contents
Introduction
Main features of gene action.
Non additive gene action
Dominance variance
Epistatic variance
Breeding procedure
steps
Factor affecting genetic variance.
Case study
3. INTRODUCTION
Gene action refers to the behaviour or mode of expression of genes in
a genetic population.
Knowledge of gene action helps in the selection of parents for use in
hybridization programmes and also in the choice of appropriate
breeding procedure for the genetic improvement of various
quantitative characters.
Gene action was first studied by Archibald Edward Garrod (1902) in
human and subsequently by other in smaller organisms like Drosophila,
Neurospora and Bacteria who was an English Physician.
4. Main features of Gene action
Gene action is measured in terms of components of genetic variance or combining
ability variances and effects.
Gene action is of two types:
1. Additive gene action (fixable variation)
2. Non-additive gene action (Un fixable variation)
Additive gene action includes additive genetic variance and additive x additive
type of epistatic variance.
Non additive gene action includes :1. Dominance variance (d) or D
2. Epistatic variance
Additive x additive variance (i) or I
Additive x dominance (j) or J
Dominance x dominance (l) or L
5. Gene action can be studied with the help of various
biometrical techniques such as diallel analysis, partial
diallel cross, triallel analyis, quadriallel analysis, line x
tester analysis, generation mean analysis, biparental
cross and triple test cross analysis.
6. Dominance Action (D)
It refers to the deviation from the additive scheme of gene action
resulting from intra-allelic interaction.
It is due to the deviation of heterozygote (Aa) from the average of
two homozygotes (AA and aa).
When d = (Aa-m) 0, gene A is showing dominance action.
Depending upon the position of heterozygote in relation to m on
the hereditary scale : Complete,
Partial,
Overdominance.
7. 1. Complete dominance: When Aa = AA or aa, a complete
dominance of A over a (positive), or vice versa (negative)
reflected.
Aa=AA, and Bb=BB, i.e, heterozygotes are equal to
homozygotes. Hence d 0 and therefore, additivity is
absent.
1. Partial Dominance: When Aa > m but <AA, or AA < m but
> aa, partial dominance of A over a (positive), or vice
versa (negative) is operative.
2. Over dominance: When Aa > AA or Aa < aa
overdominance of allele A over a (positive), or vice versa
(negative) is envisaged.
8. It is a measure of dominance gene action.
It is associated with heterozygosity &, therefore, it is
expected to be maximum in cross-pollinating crops and
minimum in self-pollinating species. It is not fixable &,
therefore, selection for traits is not fixable.
It is chief cause of heterosis or hybrid vigour.
Specific combining ability variance is the measure of
dominance variance in diallel, partial diallel and line x
tester cross analysis.
Dominance variance gets depleted through selfing or
inbreeding.
In natural breeding populations, dominance variance is
always lesser than additive variance.
Main features:
9. Epistatic (inter-allelic interaction) (I)
It refers to the deviation from additive scheme as a consequence of
inter-allelic interaction, i.e., interaction between alleles of two or
more different genes or loci.
Main features:
Epistatic variance includes both additive and non-additive
components.
It is of three types : Additive x Additive
Additive x Dominance
Dominance x Dominance
First type of epistasis is fixable and therefore, selection is effective
for traits governed by such variance.
10. Last two type of epistatic variances are unfixable – heterosis
breeding may be rewarding.
In case of generation mean analysis, the epistatic gene
interactions are classified on the basis of sign (negative or
positive) of (h) and (l) into 2 types: complementary
duplicate
• When (h) and (l) have the same sign, it is called complementary
type.
• When (h) and (l) have opposite sign, it is termed as duplicated
tpe of epistasis.
In the natural plant breeding population, epistatic variance has
the lowest magnitude.
11. Breeding procedure to be followed
Heterosis breeding
Population improvement by recurrent selection for sca
12. Steps involve in gene action
1. Selection of genotypes.
2. Making crosses.
3. Evaluation of material.
4. Analysis of data.
13. 1. Selection of genotypes: include varieties, strains or germplasm lines.
2. Making crosses: The selected genotypes are crossed according to the
mating design to be used.
Choice of mating design depends on the type of genetic material. The
mating designs, diallel, partial diallel, and line x tester analysis are
commonly used for estimation of genetic variances from single crosses.
• Triallel analysis : used for estimation of genetic variances in three-
way crosses.
• quadriallel analysis : evaluation of double crosses.
• Triple test cross analysis provides information about the presence or
absence of epistasis in addition to the estimates of additive and
dominant components.
• Three biometrical techniques ,viz., generation mean analysis, triallel
analysis and quadriallel analysis provide information about all the
three components of genetic variance, viz., additive, dominance and
epistatic variances.
14. 3.) Evaluation of material:
The crosses made among selected genotypes are
evaluated along with parents in replicated trials and
observations are recorded on various quantitative
characters.
4) Analysis of Data:
The biometrical analysis of data is carried out as per
the mating design adopted. Diallel , partial diallel,
line x tester analysis and biparental cross analysis
provide estimates of additive and dominance
components of genetic variance.
15. Factor affecting gene action
1. Type of Genetic Material:
The magnitude of gene action is largely governed by the type of genetic material
used for study.
In a F2 or advanced generation : the genetic variance includes additive,
dominance, and epistatic components.
Homozygous lines : the genetic material is entirely of additive and additive –
epistatic types.
2) Mode of pollination:
The gene action is greatly influenced by the mode of pollination of a plant species.
Self pollinated species : additive gene action is associated with homozygosity.
Inbreeding increase the amount of additive genetic variance in a population due to
increase , in homozygosity by way of gene fixation.
Cross-pollinating crops : Dominance gene action is associated with heterozygosity.
16. 3)Mode of Inheritance:
Polygenic characters are governed by both additive and non-
additive type gene action , though the additive gene action is
predominant in the expression of such characters.
On the other hand, oligogenic traits are primarily governed by non
–additive type of gene action.
4) Sample size:
The estimates of genetic variance are influenced by the sample size
on which the computation is based. Sample size should be adequate
to obtain consistent and meaningful results. Small sample may not
provide estimates of sufficient reliability.
17. Case study
Gene action of fruit yield and quality traits in okra (Abelmoschus esculentus (L.) Moench)
were studied through half diallel analysis of 28 F1 hybrids derived by crossing 8 parental
lines. The study indicated the preponderance of non-additive gene action for days to 50%
flowering, nodes per plant, fruit length, fruit diameter, plant height, fruits per plant and
mucilage and a preponderance of additive gene action for days to first picking, first fruit
producing node, internodal length, average fruit weight and harvest duration. For fruit
yield per plant and dry matter, only dominant component of variance was observed which
revealed the presence of non-additive gene action, hence, heterosis breeding is required to
be followed for exploitation of these traits.
18. The study was carried out to determine the type of gene action, genetic parameters of yield
and other quantitative traits by crossing 8 diverse maize inbred lines in complete diallel
fashion. Seed of F1 population along with their parents was planted in randomized complete
block design replicated thrice. The estimates of components of genetic variation revealed
that non additive genetic effects were more pronounced in the inheritance of plant height,
days to 50% tasseling, days to 50% silking, ear height and grain yield per plant. Directional
dominance was observed for all the characters under study. The graphic analysis showed
that all the characters were under the genetic control of over dominance type of gene action,
therefore, the material can easily be exploited for heterotic effect.