0:05 [Music]
0:14 hello and welcome to explore bio
0:16 i have met several students studying
0:18 molecular biology finding the topic of
0:20 transcriptome difficult
0:22 so today i am starting a new series of
0:24 videos on transcriptome where you will
0:26 learn about the importance of
0:27 transcriptomic study
0:28 its applications basic workflow how it
0:31 is done
0:32 data analysis important terms such as
0:34 reads transcripts
0:36 assembly annotation differential
0:38 expression and lot more stuffs
0:40 i will try to make the topic simple yet
0:42 covering important aspects of
0:44 transcriptomics
0:45 i am sure after listening to these you
0:47 will say that learning transcriptome is
0:48 easy
0:49 i request you to be consistent with all
0:51 my videos to get most out of them
0:55 this is the first an introductory video
0:57 on transcriptome so i will be covering
0:59 briefly about the role of genome
1:01 if you have watched my previous videos
1:03 you might know that our heritage
1:05 information
1:06 in the form of genome which is stably
1:08 transferred to further generation
1:10 thus the major role of genome is
1:12 information storage and transmission
1:15 the life also has an amazing mechanism
1:17 of developing genetic variability in the
1:18 genome through several mechanisms such
1:20 as recombination and mutations
1:22 i highly recommend you to watch few of
1:24 my videos to become clear about genome
1:27 its storage its different fades etc
1:31 i have tried to clear the differences
1:32 between the genome genes
1:34 dna and chromosome you may watch them
1:37 later
1:37 their links are given in the description
1:39 below
1:41 the genome content and genes remain
1:43 almost the same in all the cells of an
1:45 organism
1:47 but for responding to specific
1:48 environmental change or developmental
1:50 stage
1:51 different tissues or the cells needs to
1:54 decode this genomic information
1:55 differentially and suitably
1:57 for this specific set of genes are
1:59 transcribed to rna
2:01 which are short-lived messenger
2:02 molecules the transcriptome is a
2:04 complete set of rna
2:06 transcribed in a cell or tissue at a
2:08 specific time
2:09 as transcriptome refers to the expressed
2:11 part of the genome it is also known as
2:13 the functional genome
2:15 the study or the analysis of
2:17 transcriptome is known as
2:18 transcriptomics
2:21 it provides a good estimation about the
2:23 cellular state in terms of gene
2:25 expression
2:26 transcriptome generally refers to the
2:28 mrna that codes for protein
2:30 but it can also be used to study
2:32 non-coding rnas such as mi rna
2:34 long non-coding rnas pvrna etc
2:38 in contrast to the genome which is
2:40 almost the same
2:41 overall transcript level or the
2:43 transcriptome is very dynamic and this
2:45 is essential too
2:47 variability in transcription is one way
2:50 an organism respond to internal and
2:52 external environmental changes and
2:53 regulate their growth
2:55 development and survival for example
2:58 if a plant come across a heat stress
3:00 then it needs to produce something
3:03 that can protect it against the stress
3:05 the plant does so by expressing heat
3:07 responsive genes
3:09 so you see that the transcript of those
3:11 genes increase after heat stress
3:13 when the conditions again become normal
3:16 the transcript level again becomes the
3:17 normal
3:18 this way the dynamic nature of
3:20 transcriptome is very important
3:23 so there are two major ways to study a
3:25 transcriptome
3:27 the first one is a hybridization based
3:29 microarray technique and the other one
3:31 is sequencing based or the rna-seq
3:33 technique
3:35 in microarray a predetermined set of
3:37 probes representing sequence of gene
3:39 fragments are fixed on a solid chip
3:41 the major limitation of this technique
3:43 is that gene sequence needs to be known
3:45 for designing the chip
3:47 thus for non-model species that like
3:49 genomic sequence information
3:51 microarray is not a viable option as the
3:55 chips are not readily available
3:56 and needs to be designed and designing a
3:58 chip is very costly
4:00 on the other hand with the improvement
4:02 of next generation sequencing
4:03 technologies and reduction in the cost
4:05 of sequencing
4:06 rnsc has become a popular choice for
4:08 transcriptomic studies
4:10 moreover rna-seq being a sequencing
4:13 based approach does not require prior
4:15 genomic information
4:16 which makes it suitable to analyze
4:18 transcriptomes in non-model species too
4:23 transcriptome analysis of two main
4:25 purpose the first is the identification
4:28 of genes and their isoforms also known
4:30 as the qualitative estimation
4:32 and the second is to estimate the gene
4:34 expression or the relative expression in
4:36 different biological samples
4:38 also known as quantitative estimation
4:41 thus transcriptome is very useful
4:42 technique to compare expressional
4:44 changes in contrasting samples
4:46 or after various treatments it provides
4:48 clues about possible function of
4:50 different set of genes based on their
4:52 expression
4:54 rna-seq provides information about the
4:55 rare transcripts with lower expression
4:58 which was difficult with microarray
5:00 recent advancement has made it possible
5:02 to sequence and provide expression
5:04 profiles
5:05 of single cells too transcriptome can be
5:09 used to compare the expressional changes
5:11 in dc's compared to the healthy samples
5:14 identification of important biomarker of
5:17 gene involved in pathogenesis or other
5:19 traits
5:20 as it provides the transcript sequence
5:22 it helps in identification of genes
5:25 it may be used to see the effect of
5:27 drugs on cells
5:29 it can also be used to study the s p
5:32 variants
5:33 across the samples
5:38 so that's all for the today's video in
5:40 my next video i will start discussing
5:42 about the basic workflow and the steps
5:44 in the transcriptome sequencing
5:46 if you like the video do share with your
5:47 friends comment about what new you
5:49 learned today
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5:52 latest uploads watch my playlist to find
5:54 my other popular videos
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