YouTube Transcript:
What is transcriptome? Introduction part 1: Learn from scratch (for beginners)_

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hello and welcome to explore bio
i have met several students studying
molecular biology finding the topic of
transcriptome difficult
so today i am starting a new series of
videos on transcriptome where you will
learn about the importance of
transcriptomic study
its applications basic workflow how it
is done
data analysis important terms such as
reads transcripts
assembly annotation differential
expression and lot more stuffs
i will try to make the topic simple yet
covering important aspects of
transcriptomics
i am sure after listening to these you
will say that learning transcriptome is
easy
i request you to be consistent with all
my videos to get most out of them
this is the first an introductory video
on transcriptome so i will be covering
briefly about the role of genome
if you have watched my previous videos
you might know that our heritage
information
in the form of genome which is stably
transferred to further generation
thus the major role of genome is
information storage and transmission
the life also has an amazing mechanism
of developing genetic variability in the
genome through several mechanisms such
as recombination and mutations
i highly recommend you to watch few of
my videos to become clear about genome
its storage its different fades etc
i have tried to clear the differences
between the genome genes
dna and chromosome you may watch them
later
their links are given in the description
below
the genome content and genes remain
almost the same in all the cells of an
organism
but for responding to specific
environmental change or developmental
stage
different tissues or the cells needs to
decode this genomic information
differentially and suitably
for this specific set of genes are
transcribed to rna
which are short-lived messenger
molecules the transcriptome is a
complete set of rna
transcribed in a cell or tissue at a
specific time
as transcriptome refers to the expressed
part of the genome it is also known as
the functional genome
the study or the analysis of
transcriptome is known as
transcriptomics
it provides a good estimation about the
cellular state in terms of gene
expression
transcriptome generally refers to the
mrna that codes for protein
but it can also be used to study
non-coding rnas such as mi rna
long non-coding rnas pvrna etc
in contrast to the genome which is
almost the same
overall transcript level or the
transcriptome is very dynamic and this
is essential too
variability in transcription is one way
an organism respond to internal and
external environmental changes and
regulate their growth
development and survival for example
if a plant come across a heat stress
then it needs to produce something
that can protect it against the stress
the plant does so by expressing heat
responsive genes
so you see that the transcript of those
genes increase after heat stress
when the conditions again become normal
the transcript level again becomes the
normal
this way the dynamic nature of
transcriptome is very important
so there are two major ways to study a
transcriptome
the first one is a hybridization based
microarray technique and the other one
is sequencing based or the rna-seq
technique
in microarray a predetermined set of
probes representing sequence of gene
fragments are fixed on a solid chip
the major limitation of this technique
is that gene sequence needs to be known
for designing the chip
thus for non-model species that like
genomic sequence information
microarray is not a viable option as the
chips are not readily available
and needs to be designed and designing a
chip is very costly
on the other hand with the improvement
of next generation sequencing
technologies and reduction in the cost
of sequencing
rnsc has become a popular choice for
transcriptomic studies
moreover rna-seq being a sequencing
based approach does not require prior
genomic information
which makes it suitable to analyze
transcriptomes in non-model species too
transcriptome analysis of two main
purpose the first is the identification
of genes and their isoforms also known
as the qualitative estimation
and the second is to estimate the gene
expression or the relative expression in
different biological samples
also known as quantitative estimation
thus transcriptome is very useful
technique to compare expressional
changes in contrasting samples
or after various treatments it provides
clues about possible function of
different set of genes based on their
expression
rna-seq provides information about the
rare transcripts with lower expression
which was difficult with microarray
recent advancement has made it possible
to sequence and provide expression
profiles
of single cells too transcriptome can be
used to compare the expressional changes
in dc's compared to the healthy samples
identification of important biomarker of
gene involved in pathogenesis or other
traits
as it provides the transcript sequence
it helps in identification of genes
it may be used to see the effect of
drugs on cells
it can also be used to study the s p
variants
across the samples
so that's all for the today's video in
my next video i will start discussing
about the basic workflow and the steps
in the transcriptome sequencing
if you like the video do share with your
friends comment about what new you
learned today
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