W1Lec. Introduction to Human Genetics; The Human Genome Flashcards
I. Basic terms
2. What is Genetics?
Science focusing on induvidual genes, the inheritence and variability
I. Basic terms
1. What is Genome?
the complete genetic material of the cell
I. Basic terms
3. What is Genomics?
science focusing on the entire genome and the interection of genes
I. Basic terms
4. What is Epigenetics?
science focusing on inherited, however , not DNA sequence encoded changes of gene expression
II. Scope of Genetics
1. What are the 2 important factors of scope of genetics?
- Stability
- Variability
II. Scope of Genetics
2. Why is stability an important factor in scope of genetics?
Inheritance
- of a trait (phenotype)
- constant chromosomal number
II. Scope of Genetics
3. Why is Variability an important factor of scope of genetics?
- Meiotic recombination
- Crossover
- Random assortment
- Fertilization
- Mutations / Polymorphisms - Epigenetic variations
III. Mendel’s law
1. What are the 3 laws of Mendel?
- Law of segregation
- Law of uniformity
- Law of Independent assortment
III. Mendel’s law
2. What is law of Segregation?
The 2 alleles for each gene separate during gamete formation
III. Mendel’s law
3. What is law of uniformity?
F1 generation after monohetorozygotic cross
III. Mendel’s law
3. What is law of uniformity?
F1 generation after monohetorozygotic cross
III. Mendel’s law
4 What is law of independent assortment?
Alleles of genes on nonhomologous chromosomes assort independently during gamete formation
How many known loci are there?
16037
How many human genes are there?
24 000
How many monogenic human genetic diseases follow Mendelian inheritance are there?
9 000
What causes the differences in numbers?
- Not all loci and genes are known yet
- Many diseases / traits are not defined by one gene =
complex traits / diseases - Even different parts and defects of one particular gene may be responsible for different traits / diseases
What are the types of inheritance?
What is vertical gene transfer?
Transfer of information from generation to generation (from parent to offspring or from cell to daughter cells)
What is horizontal gene transfer?
Transfer of information between same or different organisms within a generation (prokaryots and prokaryots or pro- and eukaryotes or eukaryotes and eukaryotes)
Explain Horizontal gene transfer between bacteria
3 types
- Bacterial transformation
- Bacterial transduction
- Bacterial conjunction
What is the length of DNA?
2 m / cell nucleus
- In our body the DNA is 651 times longer than the distance of the Earth and the Moon
Do all the cells of our body contain the same amount of DNA?
- Somatic cells and germ cells differ
- In somatic cells it also depends on the presence and number of nuclei (e.g. RBC, skeletal muscle cell)
- Somatic cells also differ because of different stages of the cell cycle
Is the DNA sequence identical in all somatic cells?
No, in T cells and B cells it is different (somatic gene rearrangement)
What does the DNA encode for?
RNAs and proteins
Lipids and carbohydrates are non-templated
What are Building block s of DNA?
- Nucleoside = 2 deoxyribose + purine/pyrimidine
- Nucleotide = phosphoric acid + 2 deoxyribose + purine/pyrimidine
Give the structure of DNA
How many base pairs/ human somatic cell are there?
2x 3x10^9 base pairs
What is the antisense or nonsense or non-coding strand?
- The antisense or nonsense or non-coding strand: it is the active strand that participates in transcription of sense
(5’AUG …3’) mRNA. - Single strands are written by convention 5’-3’.
Transcription followed by ___ based on the genetic code
translation
What are the 5 features of genetic code?
- Three letter code (triplets)
- Redundancy - Wobbling
One aa may be coded by several triplets
(20 aa – 61 triplets)
3 stop codon (TAA, TAG, TGA) - Comma-free, Non-overlapping
- Almost universal
- No ambiguity (1 codon encodes for 1 amino acid only)
Describe the nucleosomal organization DNA
What are 2 types of chromatin?
- euchromatin
- Heterochromatin
Describe these 2 picture
(a) Euchromatin
- Uncoiled chromatin filament with nucleosomes “genes on”: active
(b) Heterochromatin
- Interphase chromatin filament: „genes off”: inactive
(30 nm )
What is the role of histone code?
The histone code (chemical modification of histones) regulates the chromatin packing and gene transcription
- AC: Acetylation
- Methylation
- P: phosphorylation
- Ubiquitylation
Describe the formation of chromosomes
Describe the formation of chromosomes
What is gene?
the unit of inheritance, part of the DNA or RNA
What is locus?
location of a given gene on a chromosome
What is gene product?
– RNA
– Protein
What is allele?
allelomorph genes
* Gene variant at a given locus
* Wild type allele: the most frequent variant of a given gene in nature
What is the Structure of the eukaryotic protein coding gene?
What is the structure of mRNA?
What is Genotype?
genetic composition of characteristics for an individual or a locus
What is phenotype?
Measurable and observable features of a cell or and individual
What is Phenocopy?
Trait which is caused by environmental conditions, that matches a phenotype which is determined by genetic factors.
Explain Inheritance versus environmental effects
What is homozygote?
identical alleles at the same loci of the chomosome pair
What is heterozygote?
Different alleles at the same loci of the chomosome pair
What is hemizygote?
Carries only a single copy of the gene
What is dominant allele?
a gene variant that phenotypically always results in a given chracateristics (even in heterozygotes)
What is recessive allele?
A gene variant that manifests phenotypically in homo- and hemizygotes only
What are special problems of humangenetics to study the inheritance?
- Small (nuclear) families, mosaic families
- Technical (long life span of human)
- Lack of long term and exact records
- Except aristocrats/Royal families
- e.g. Inheritance of Habsburgian lip – mandibular prognathism - ELSI (Ethical, Legal, and Social Issues), gene ethics
What is the purpose of Methods of humangenetics?
- To understand the correlation between genotype and phenotype
- Possibility to develop genetically modified organisms
- Extrapolation of common/similar traits from animal studies
In the Methods of human genetics, we find out Extrapolation of common/similar traits from animal studies.
-> What is the example for it?
The same mutation of the same gene is responsible for red hair color and red fur
Give examples of Methods of human genetics
- Pedigree analysis
- Twin studies
- Population screening
Explain this pyramid
- Genome = the complete genetic material of the cell
- Transcriptome = the total RNA content of the cell
- Proteome = the total protein content of the cell
- Metabolome = the total small molecule content of the cell
What is the difference between classical genetics and genomics?
- Classical Genetics - investigates the inheritance of one or few traits
- Genomics - investigates the whole genome, the function, structure and interactions of the complete gene-set.
(No definite difference between the two terms, even in the scientific usage, genetics and genomics are often interchangeable.)
How are nuclear and mitochondrial genomes inherited?
- Nuclear DNA is inherited from all ancestors
- Mitochondrial DNA is inherited from a single lineage
What are the differences between nuclear DNA and mtDNA?
How many base pairs and genes are there in mitochondrial genome?
16 569 basepairs, 37 genes
Several mitochondrial genes had been translocated to the ___
nucleus
Describe Organization of the nuclear genome
Describe The structure of the human genome
What make people different from each other?
Between two people there are 3 million bp differences – every 1000nd bp are different.
What is Single nucleotide variant (SNV)?
- A variation in a single nucleotide without any limitations of frequency.
- It may arise in somatic cells (e.g., caused by cancer), also called a single-nucleotide alteration.
What are Repetitive sequences in the genome?
What are the 2 methods of transposition?
- “cut and paste” (class II)
DNA transposons - “copy and paste” (class I) retrotransposons
What is the Human Genome Project?
Project goals were to
1. identify all the approximately 20,000-25,000 genes in human DNA
2. determine the sequences of the 3 billion chemical base pairs that make up human DNA,
3. store this information in databases,
4. improve tools for data analysis,
5. transfer related technologies to the private sector, and
6. address the ethical, legal, and social issues (ELSI) that may arise from the project.
Give the processes that human genome project speed up?
What are major results of ENCODE (Encyclopedia of DNA Elements Project?
- Presumably a much larger proportion of the human DNA is active than what we thought previously:
- The majority of the non-coding regions participate in regulation of the expression of the coding 1%
Describe Age of omics
- The term ‘genomics’ also involves the special genomic methods and bioinformatics.
- Genomics is part of the systems biology.
- Several subtypes of genomics, e. g.
– structural genomics,
– comparative genomics,
– plant genomics,
– human genomics,
–pharmacogenomics -thestudythe interaction of genes and drugs
– Nutrigenomics (to study the interaction of genes and nutrition)
– etc.
The difference between the human and chimpanzee genomes is ___ only
4%
Do genetics influence psychological well-being? How?
YES!!
Genes play a role in self-control, decision making, sociability, sense of purpose, how well to get on with people, and ability to continue learning and developing.
How does Genetics influence political beliefs?
Genetic information might be used to predict variations in political opinion more reliably than we can use genetic information to predict longevity and alcoholism.
