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Feb 26 Adv Gen

David Peyton2021-02-26
71 views|3 years ago
💫 Short Summary

The video covers DNA sequencing, X-inactivation in calico cats, genetic mutations in horses affecting coat colors, and the use of PCR in genetic testing. It discusses the impact of mutations on animals, the significance of specific chromosomes in determining coat colors, and the application of PCR in analyzing genetic variations in horses. Researchers use PCR to identify genetic mutations quickly and efficiently in horses, providing practical alternatives to sequencing methods. The video emphasizes the importance of understanding genetic patterns in animals for breeders and veterinarians to ensure their health and well-being.

✨ Highlights
📊 Transcript
Overview of DNA sequencing chemistry.
Nucleotides and synthesis termination are key components.
Reading multiple sequences and shotgun sequencing methods are discussed.
PCR reflex and its application in genotyping Sabino horses are explained.
Coat color variations in animals, like calico cats, are linked to the kit gene mutation.
X-inactivation in female cats leads to calico cats having patches of different colors on their coat.
The process results in cells expressing different coat color genes inherited from each parent.
The choice made by a cell during x-inactivation is maintained throughout development, resulting in specific areas expressing the corresponding color.
X-inactivation explains the unique coat patterns seen in calico cats.
This process highlights the genetic complexity behind coat color determination in animals.
Discussion on calico cats and how their coat color is determined by specific chromosomes.
Male calico cats are rare and likely infertile due to chromosomal abnormalities.
Klinefelter's syndrome can result in unique coat colors in cats due to chromosomal abnormalities.
Genes like MC1R and tyrosinase play a role in determining coat color variations in domesticated animals.
Selective breeding for specific traits contributes to the variability in coat colors among cats and dogs.
Differences in effects of a mutation causing piebaldism in mice versus humans.
Mutation in mice can lead to detrimental effects like deafness, anemia, sterility, and mast cell deficiency.
Severity of the mutation in mice may be due to homozygous conditions and inbred colonies.
Different gene mutations could have varying impacts in different species, with more severe mutations in mice compared to humans.
Emphasis on the need for further research to understand genetic differences.
Announcement of upcoming quiz and exam schedule.
Quiz scheduled for Monday, open all day.
Exam set for the following Monday, with three more lectures before exam material is covered.
Real-time PCR (qPCR) discussed as more definitive test than antibody tests.
Nasal swab tests provide results in 24 hours and analyze RNA present in the body.
Study on RNA splicing in horses with a genetic mutation.
Researchers are using RNA isolation from tissue samples to detect the virus through quantitative PCR reactions.
Specific focus on reverse transcriptase PCR to analyze messenger RNA and DNA, with a focus on exon 16 and exon 18.
Horses with a mutation were found to be skipping exon 17, with homozygous horses more likely to skip.
Majority of functional transcripts included exon 17, indicating a splicing issue being highlighted in the study.
Highlights of Exxon 17 Investigation
Investigation focused on intron and exon sequences, finding snips and variations.
Association comparison narrowed findings to one phenotype.
Mutation identified as t to a substitution in intron, providing a tool for researchers to distinguish mutated DNA.
PCR rift flip used to screen individuals quickly for mutation.
The PCR rifflip assay and its significance in DNA fingerprinting.
The assay involved using a restriction enzyme to cut genomic DNA into unique fragments.
This method was crucial for identifying genetic variations and establishing DNA profiles.
PCR revolutionized genetic testing in the mid to late 80s, leading to advancements in DNA analysis and forensic science.
Development of DNA testing using restriction fragment length polymorphisms (RFLPs).
RFLPs were initially used to test familial relationships and establish British citizenship for returnees.
Colin Pitchfork was the first murderer convicted using DNA evidence from two rape victims.
PCR techniques allow for copying specific gene regions for analysis, with mutations affecting restriction enzyme sites.
Changes in restriction enzyme sites can alter DNA cutting patterns, providing crucial forensic evidence.
PCR analysis for studying genetic variations in horses.
PCR allows for targeted examination of single nucleotide changes in genomic DNA.
Results of PCR analysis showed differences in band sizes between wild type and mutated alleles.
Mutation led to the elimination of an enzyme site, resulting in altered band patterns.
Presenter noted a discrepancy in nucleotide counts, potentially due to a typographical error.
Summary of DNA Assay Process for Horse Genetic Mutations
The process involves PCR, restriction digest, and gel electrophoresis to analyze horse DNA samples for mutations.
Results show distinct bands for wild type, heterozygous, and homozygous mutant horses, with band patterns indicating genetic variations.
The assay is cost-effective, quick, and efficient compared to sequencing, providing a practical way to identify genetic mutations in horses.
This method offers a simpler and more affordable alternative to complex and expensive techniques for genetic analysis in horses.
Highlights of Genetic Testing Results using Gel Electrophoresis:
The segment focuses on homozygous mutations and wild type DNA in genetic testing results.
Band patterns in DNA samples are analyzed to identify specific genetic mutations.
The importance of control lanes in the gel for comparison and result interpretation is emphasized.
Unused primers in the PCR reaction are explained, including the excess primer added to prevent reagent limitation.
The length of primers and their separation on the gel are discussed to aid in the visualization of DNA fragments.
Process of PCR and Gel Electrophoresis Analysis.
Bright bands in the gel indicate high DNA concentration due to dye absorption.
The brightness is proportional to DNA size, with homozygous samples showing more template material.
The method is a good indicator of DNA concentration, although not perfectly linear.
An association study on walking horses was mentioned to test the PCR results with a larger family sample.
Genetic mutation in horses leading to white coat color identified through research on 320 horses from 13 breeds.
Horses homozygous for the mutation were white, while those with a single allele displayed sabino, multi-patterned, or white coats.
Phenotypically white horses heterozygous for the mutation also tested positive for other patterns.
The Ovaro pattern, also known as Overo Lethal White Foal Syndrome, results in foals born with a dysfunctional digestive system and death within days.
Understanding these genetic patterns is crucial for breeders and veterinarians to ensure horse health and well-being.
Importance of genetic heterogeneity and single nucleotide polymorphism in intron splice site.
Researchers analyzed a mutation compared to an ideal splice sequence to determine impact.
Splice score calculated using an app based on a formula from a previous publication.
Wild type site found to be stronger than mutant site.
Emphasis on relative comparison and discussion on data blip regarding mutation's position relative to splice site.
Discussion on mutations at the exon-intron junction and their significance.
Conservation at this position among animals highlights the importance of intron mutations.
Analysis of different nucleotides at the junction, with one nucleotide showing the highest frequency.
The segment concludes with an apology for exceeding time and a promise to continue the discussion in the next meeting.