Gene mapping means the mapping of genes to specific locations on chromosomes.
Such maps indicates the positions of genes in the genome and also distance between them.
RNA interference (RNAi): Cellular process by which an mRNA is targeted for degradation by a dsRNA with a strand complementary to a fragment of such mRNA.
Gene mapping means the mapping of genes to specific locations on chromosomes.
Such maps indicates the positions of genes in the genome and also distance between them.
RNA interference (RNAi): Cellular process by which an mRNA is targeted for degradation by a dsRNA with a strand complementary to a fragment of such mRNA.
Presenting the probability in genetics; Product law, Sum law, Binomial Theorem and Chi-square. Also brief explanation on pedigree analysis and genetic disorders of autosomal dominant and recessive.
The idea of chromosomal Linkage. It starts with understanding the Mendel's law of segregation and Independent assortment and later discusses why certain traits does not follows 9:3:3:1 ratio as in Mendel's law of Independent assortment. Also briefly covers the Genetic mapping and phenotypic mapping unit.
Presenting on the chromosomal aberration both in structure and number. Insight view in some disorders caused by chromosomal aberration including down syndrome, Patau syndrome, Edward syndrome and XY sex chromosome.
Population Genetics & Hardy - Weinberg Principle.pdfSuraj Singh
This presentation is all about the population genetics.
In this presentation I would like to explain about the population genetics, calculation of allele frequencies, calculation of frequencies of sex - linked alleles.
Also there is a detailed explanation of Hardey-Weinberg equilibrium or principle.
In the last there are few key points regarding with the assumptions and steps for the Hardy-Weinberg principle.
Earliest Galaxies in the JADES Origins Field: Luminosity Function and Cosmic ...Sérgio Sacani
We characterize the earliest galaxy population in the JADES Origins Field (JOF), the deepest
imaging field observed with JWST. We make use of the ancillary Hubble optical images (5 filters
spanning 0.4−0.9µm) and novel JWST images with 14 filters spanning 0.8−5µm, including 7 mediumband filters, and reaching total exposure times of up to 46 hours per filter. We combine all our data
at > 2.3µm to construct an ultradeep image, reaching as deep as ≈ 31.4 AB mag in the stack and
30.3-31.0 AB mag (5σ, r = 0.1” circular aperture) in individual filters. We measure photometric
redshifts and use robust selection criteria to identify a sample of eight galaxy candidates at redshifts
z = 11.5 − 15. These objects show compact half-light radii of R1/2 ∼ 50 − 200pc, stellar masses of
M⋆ ∼ 107−108M⊙, and star-formation rates of SFR ∼ 0.1−1 M⊙ yr−1
. Our search finds no candidates
at 15 < z < 20, placing upper limits at these redshifts. We develop a forward modeling approach to
infer the properties of the evolving luminosity function without binning in redshift or luminosity that
marginalizes over the photometric redshift uncertainty of our candidate galaxies and incorporates the
impact of non-detections. We find a z = 12 luminosity function in good agreement with prior results,
and that the luminosity function normalization and UV luminosity density decline by a factor of ∼ 2.5
from z = 12 to z = 14. We discuss the possible implications of our results in the context of theoretical
models for evolution of the dark matter halo mass function.
Introduction:
RNA interference (RNAi) or Post-Transcriptional Gene Silencing (PTGS) is an important biological process for modulating eukaryotic gene expression.
It is highly conserved process of posttranscriptional gene silencing by which double stranded RNA (dsRNA) causes sequence-specific degradation of mRNA sequences.
dsRNA-induced gene silencing (RNAi) is reported in a wide range of eukaryotes ranging from worms, insects, mammals and plants.
This process mediates resistance to both endogenous parasitic and exogenous pathogenic nucleic acids, and regulates the expression of protein-coding genes.
What are small ncRNAs?
micro RNA (miRNA)
short interfering RNA (siRNA)
Properties of small non-coding RNA:
Involved in silencing mRNA transcripts.
Called “small” because they are usually only about 21-24 nucleotides long.
Synthesized by first cutting up longer precursor sequences (like the 61nt one that Lee discovered).
Silence an mRNA by base pairing with some sequence on the mRNA.
Discovery of siRNA?
The first small RNA:
In 1993 Rosalind Lee (Victor Ambros lab) was studying a non- coding gene in C. elegans, lin-4, that was involved in silencing of another gene, lin-14, at the appropriate time in the
development of the worm C. elegans.
Two small transcripts of lin-4 (22nt and 61nt) were found to be complementary to a sequence in the 3' UTR of lin-14.
Because lin-4 encoded no protein, she deduced that it must be these transcripts that are causing the silencing by RNA-RNA interactions.
Types of RNAi ( non coding RNA)
MiRNA
Length (23-25 nt)
Trans acting
Binds with target MRNA in mismatch
Translation inhibition
Si RNA
Length 21 nt.
Cis acting
Bind with target Mrna in perfect complementary sequence
Piwi-RNA
Length ; 25 to 36 nt.
Expressed in Germ Cells
Regulates trnasposomes activity
MECHANISM OF RNAI:
First the double-stranded RNA teams up with a protein complex named Dicer, which cuts the long RNA into short pieces.
Then another protein complex called RISC (RNA-induced silencing complex) discards one of the two RNA strands.
The RISC-docked, single-stranded RNA then pairs with the homologous mRNA and destroys it.
THE RISC COMPLEX:
RISC is large(>500kD) RNA multi- protein Binding complex which triggers MRNA degradation in response to MRNA
Unwinding of double stranded Si RNA by ATP independent Helicase
Active component of RISC is Ago proteins( ENDONUCLEASE) which cleave target MRNA.
DICER: endonuclease (RNase Family III)
Argonaute: Central Component of the RNA-Induced Silencing Complex (RISC)
One strand of the dsRNA produced by Dicer is retained in the RISC complex in association with Argonaute
ARGONAUTE PROTEIN :
1.PAZ(PIWI/Argonaute/ Zwille)- Recognition of target MRNA
2.PIWI (p-element induced wimpy Testis)- breaks Phosphodiester bond of mRNA.)RNAse H activity.
MiRNA:
The Double-stranded RNAs are naturally produced in eukaryotic cells during development, and they have a key role in regulating gene expression .
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.
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.
What is greenhouse gasses and how many gasses are there to affect the Earth.moosaasad1975
What are greenhouse gasses how they affect the earth and its environment what is the future of the environment and earth how the weather and the climate effects.
This presentation explores a brief idea about the structural and functional attributes of nucleotides, the structure and function of genetic materials along with the impact of UV rays and pH upon them.
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.
Multi-source connectivity as the driver of solar wind variability in the heli...Sérgio Sacani
The ambient solar wind that flls the heliosphere originates from multiple
sources in the solar corona and is highly structured. It is often described
as high-speed, relatively homogeneous, plasma streams from coronal
holes and slow-speed, highly variable, streams whose source regions are
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.
2. Constant Allele Frequencies
• Population genetics looks at phenotypes and
genotypes among large numbers of individuals.
• Tracking allele frequencies from one generation
to the next can reveal evolution in action.
Prepared by Pratheep Sandrasaigaran
3. Hardy-Weinberg Equilibrium
• In 1908 Godfrey Harold Hardy (mathematician) and
Wilhelm Weinberg (German physician).
• Independently (never met) used algebra to explain
how genotypic frequencies are related to allele
frequencies.
Prepared by Pratheep Sandrasaigaran
4. Relating alleles to genotypes
• What is an equilibrium?
• What is Hardy-Weinberg equilibrium?
• Allele and genotype frequencies will remain
unchanged, generation after generation, as long as
certain conditions are met; four assumptions.
• When one of the assumptions isn’t met, the
relationship between allele frequency and
genotype frequency usually starts to fall apart
Prepared by Pratheep Sandrasaigaran
5. Four conditions for Hardy-
Weinberg Equilibrium
• The organism must reproduce sexually and be
diploid.
• The allele frequencies must be the same in both
sexes.
• The loci must segregate independently.
• Mating must be random with respect to genotype
Prepared by Pratheep Sandrasaigaran
6. Graphically illustrated Hardy-
Weinberg Equilibrium
• The Y axis is genotypic frequency in
percentage.
• The X axis is the frequency of the
recessive allele in percentage.
• What proportion of the population is
homozygous aa when the allele
frequency of a is 40 percent?
• 20 percent of the population is
expected to be aa when 40 percent
of the population carries the a allele
Prepared by Pratheep Sandrasaigaran
7. Relating alleles to genotypes
• If frequency of allele a is 40%, then the
frequency of allele A is 60%, because p
+ q = 1.
• What is this line for?
• The frequency of heterozygotes, Aa.
• The highest proportion of the
population that can be heterozygous is
50 percent
Prepared by Pratheep Sandrasaigaran
8. Relating alleles to genotypes
• When 50 percent of the population is
heterozygous, the Hardy-Weinberg
equilibrium predicts that 25 percent of
the population will be homozygous for
the A allele, and 25 percent will be
homozygous for the a allele.
• This situation occurs only when p is
equal to q.
• p = q = 50%
Prepared by Pratheep Sandrasaigaran
9. Relating alleles to genotypes
• The relationship between allele
frequencies and genotype
frequencies is described by the
equation p2
+ 2pq + q2
.
• Thus, the line marked aa is
described by the equation p2
.
• The line marked AA is described by
the equation q2
.
• 2pq describes the frequency of
heterozygotes (Aa)
Prepared by Pratheep Sandrasaigaran
10. Violating the law
• There are several ways that populations can wind
up out of Hardy-Weinberg equilibrium.
• How to ensure no violation?
– Large population
– No mutation
– No natural selection
– No migration
– Randomly mating populations
Prepared by Pratheep Sandrasaigaran
11. Solving a Problem
• Consider an autosomal recessive trait: a middle finger shorter than
the second and fourth fingers.
• If we know the frequencies of the dominant and recessive alleles,
then we can calculate the frequencies of the genotypes and
phenotypes and trace the trait through the next generation.
Prepared by Pratheep Sandrasaigaran
12. Solving a Problem
• The dominant allele D confers normal-length
fingers; the recessive allele d confers a short
middle finger.
• If 9 out of 100 individuals in a population have
short fingers (dd) —the frequency is 9/100 or
0.09.
• Since dd equals q2
, then q equals 0.3.
• Since p + q = 1.0, knowing that q is 0.3 tells us
that p is 0.7
Prepared by Pratheep Sandrasaigaran
13. Solving a Problem
• Calculate the proportions of the three genotypes
that arise when gametes combine at random.
• Homozygous dominant = DD (p2
)
• 0.7 × 0.7 = 0.49
• Homozygous recessive = dd (q2
)
• 0.3 × 0.3 = 0.09
• Heterozygous = Dd + dD (2pq)
• (0.7)(0.3) + (0.3)(0.7) = 0.42
Prepared by Pratheep Sandrasaigaran
14. Solving a Problem
• Within a population of mouse, the color black (B)
is dominant over the white color. 40% of all mice
are white. Calculate the following
– The percentage of mice in the population
those are heterozygous.
– The frequency of homozygous dominant
individuals
Prepared by Pratheep Sandrasaigaran