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Mar 1 Adv Gen

David Peyton2021-03-01
53 views|3 years ago
💫 Short Summary

The video segment explores genetic terms such as co-segregation and linkage disequilibrium, quantitative PCR in virus testing and DNA sequencing, mutations impacting splice sites in horses, and the significance of genetic mutations in tyrosine kinase receptors across various animals. Researchers delve into the genetic causes of coat color variation in dogs, alopecia, and the pleiotropic effects of gene defects on multiple outcomes. The importance of understanding gene expression, splicing trends, and protein function in cellular pathways is emphasized. The study aims to deepen insights into genetic inheritance and phenotypic traits in animals through advanced sequencing techniques and practical applications.

✨ Highlights
📊 Transcript
Discussion on co-segregation and linkage disequilibrium in genetics and DNA.
02:53
Co-segregation refers to traits always appearing together, while linkage disequilibrium relates to the randomness of genetic markers.
Linkage was used before the discovery of DNA as the hereditary agent.
Co-segregation is seen as a more intuitive term compared to linkage disequilibrium.
Importance of context in determining the accuracy of genotypes in different population sizes is emphasized.
Use of quantitative PCR in virus testing and DNA sequencing.
05:21
Real-time PCR is utilized by the FBI for individual identification through genetic loci.
Quantitative PCR yields precise numerical data but is costly and time-consuming.
Choosing the appropriate technique is crucial based on practicality and cost-effectiveness.
PCR riffle is presented as a faster and more affordable option for specific applications, demonstrating the balance between advanced techniques and practical considerations in genetic testing.
Identification of a mutation upstream of a splice site in horses causing messenger RNA processing to skip exon 17.
09:53
Defects in consensus sites at exon-intron junctions can lead to less recognizable sites, impacting splicing.
The mutation discussed is slightly upstream of the consensus site, affecting the splicing process.
Sequences outside the consensus site are essential, highlighting oversimplification in teaching.
Understanding the impact of mutations on splice sites is crucial for genetic processes and molecular biology research.
Nucleotide composition influences spliceosome recognition.
11:40
Exon 17 may be skipped if it becomes less recognizable, targeting exon 18 instead.
T is found almost twice as much as expected, while A is only present five percent of the time.
Differences in nucleotide frequency impact how the spliceosome identifies sites.
Using peripheral blood cells instead of melanocytes poses limitations in investigating gene expression and cell migration.
Impact of mutation on kit expression in cells.
15:25
Use of blood cells for analysis and carrier identification.
Mutation affects splicing trends and is linked to sabino phenotype in horses.
Disrupting kinase activity has downstream effects on protein function.
Mutation leads to loss of tyrosine residue, impacting tyrosine kinase domain in various organisms.
Mutations in tyrosine kinase receptors and their impact on receptor function.
18:09
Researchers emphasize consistent sites across different animals and the importance of certain mutations.
Various color phenotypes in horses, like tobiano and lethal white syndrome, are discussed in relation to specific mutations.
Associations with mutations like the endothelin receptor b are speculated upon.
The significance of contextualizing new discoveries within existing knowledge and the complexity of phenotypes in relation to genetic mutations is highlighted.
Study on coat color variation in dogs, focusing on dobermans and weimaraners.
22:10
Use of quantitative PCR to study coat color traits as a Mendelian autosomal recessive trait.
Exploration of dilute haplotypes in different breeds and genetic variants for the MLPH gene.
Lack of causative variants for all dilute animals found in the study.
Emphasis on the importance of haplotypes in genetic inheritance and ongoing research building upon previous work.
Genetic causes of alopecia in dogs.
26:55
Melanocytes and their connection to hair follicles are examined, with a potential defect in transport being a key factor.
The term 'pleiotropic' is defined and discussed, emphasizing the importance of understanding multiple effects from a single gene.
Mention of melanophilin as an example of a potential cause of alopecia in dogs.
Debate surrounding the registration and recognition of silver labs in the dog breeding community.
Genetic changes can have pleiotropic effects, leading to multiple outcomes from a single mutation.
28:43
A gene defect can result in issues such as diluted pigment, skin inflammation, and hair loss.
Traits in animals can be selectively bred, raising ethical questions in the process.
Sequencing the 5' region of genes can help identify mutations linked to certain phenotypes in dogs of various breeds.
The research aims to gain a deeper understanding of the genetic basis of specific traits in animals.
Study on polymorphism and mutation affecting gene expression.
31:55
Researchers used quantitative reverse transcriptase polymerase chain reaction to confirm expression level differences.
Defective transport of melanosomes causes pigment clumps to accumulate in melanocytes.
Impact of mutation on animal coloration due to accumulation of pigment clumps.
Strong evidence linking mutation to observed phenotype in various species.
Research on melanosomes in mouse cells reveals insights on pigment transport mechanisms.
35:11
Mutations in proteins linked to melanosomes transport lead to clustering in cells.
Studies on mink show genetic variations in the melanophilin gene.
Three proteins are vital for the distribution of pigment granules within cells.
Understanding pigment distribution, transport, and translocation within cells is essential for addressing white pattern issues.
The roles of myosin 5a and rab27a in melanosome trafficking in melanocytes.
40:19
Myosin 5a acts as a motor on actin filaments and recruits melanophilin as a linker protein.
Rab27a is located on the surface of mature melanosomes.
Melanophilin facilitates the movement of melanosomes along actin filaments towards neighboring keratinocytes for melanin deposition.
Understanding these proteins is crucial for comprehending the melanin transfer process in melanocytes.
Importance of actin filament, rab27a, and melanofilan in melanosome transport in cells.
42:10
Myosin 5a, rab27a, and melanofilan are crucial proteins for proper transport.
Gene mutations affecting skin color in animals like cats and dogs discussed.
No causative mutations identified despite associations found.
Researchers conducted sequencing to identify potential causative polymorphisms for further testing.
Development of qPCR for measuring RNA expression.
46:09
qPCR was initially doubted due to PCR limitations in measuring RNA expression.
Advocates persisted and developed a standard method for measuring RNA expression.
Gap dh gene is used as an internal control to standardize the expression levels of other genes like melanophilin.
qPCR has become the gold standard for measuring gene expression, with Gap dh being a reliable control for gene expression studies.
PCR Process Overview
49:11
RNA is collected and converted to DNA, followed by a PCR reaction to measure DNA production.
PCR products are quantified, with the exponential phase leading to a plateau.
The amount of starting material impacts the time for reactions to plateau, with more material resulting in quicker plateauing.
Monitoring DNA levels at specific cycle points can show differences in gene expression levels, emphasizing the need to understand PCR dynamics for result interpretation.
Discussion on the use of quantitative PCR to capture information before the reaction plateaus.
52:39
Speaker hints at covering more details in the next session, including upcoming tests and review materials.
Reminder to viewers to take the quiz and mentions a lack of submissions so far.
Encouragement to generate questions about papers for discussion.
Plans to work on a review for an upcoming exam and promises to continue from there.