Materi Kuliah Dasar2 Genetika Fakultas Pertanian UGM

1. INTRODUCTION TOINTRODUCTION TO
GENETICSGENETICS

2. Why must we studyWhy must we study
genetics?genetics?

3. G×E
interaction
Health
Genetics
Environment

4. Perkembangan Publikasi
Genetika
ISI Web of Science topic search for "genetic AND disease"
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5. GeneticsGenetics
 Branch of biology dealing with heredity and variationBranch of biology dealing with heredity and variation
 Branch of biology dealing with the study of the geneBranch of biology dealing with the study of the gene
Center of Genetics:
 Unit of heredity
 Nucleic acid
 Protein synthesis
 Characteristics of
organisms
 Relationship between
genes and traits
Genetics is a broad discipline
It encompasses molecular,
cellular, organism, and
population

6. Three Major Areas of GeneticsThree Major Areas of Genetics
Classical Genetics
(Transmission)
Molecular Genetics Evolutionary
Genetics
Mendel’s Principles Genom Quantitative Genetics
Meiosis + mitosis DNA structure Population Genetics
Sex determination Chemistry of DNA Evolution
Sex linkage Gene expression Speciation
Chromosomal
mapping
Control of gene
expression
Cytogenetics DNA cloning &
Marker

7. Major Subdisciplines of Genetics
 Transmission Genetics: focuses on the transmission
of genes and chromosomes in individuals from
generation to generation.
 Molecular Genetics: focuses on the structure and
function of genes at the molecular level.
 Evolutionary genetics: focus on the study of genetic
basis of changes in organism over time
 Population Genetics: focuses on heredity in groups of
individuals for traits determined by one or only a few genes.
 Quantitative Genetics: focuses on heredity in groups of
individuals for traits determined by many genes simultaneously.

8. 1. Genome
2. Chromosome
3. Gene
4. DNA/RNA
5. Nucleic Acid
6. Protein
7. Amino Acid
The Basis of Inheritance?

9. Genome
Entirely of an organism’s heredity information
Complete set of instructions for making an organism
All of the hereditary information encoded in an
organism’s DNA.
Master blueprints for all enzymes, cellular structures &
activities
An organism‘s complete set of DNA
All the DNA contained in the cell of an organism
The collection of DNA that comprises an organism

10. Prokaryotic Organism
• Eubacteria and Archaea. Usually unicellular.
• No internal membrane-bound compartments: DNA
floats free in the cytoplasm.
• 1 circular chromosome (plus optional plasmids, which
are also circular)
• reproduction usually asexual
• sexual processes (mixing DNA from 2 individuals)
occur, but with unequal contributions from the 2
partners
• transcription and translation simultaneous

11. Prokaryotic genomes
 Most have a single, double-
stranded circular DNA molecule
 Usually without introns
 Since there is no nucleus, the
DNA floats freely within the cell
 Proteins cause the DNA to coil
tightly forming a nucleoid
region
 Relatively high gene density
 Often indigenous plasmids are
present

12. Eukaryotic Organism
• Plants, animals, fungi, protistas. Often multicellular.
• DNA contained within a membrane-bound nucleus.
• linear chromosomes (usually more than 1)
• careful division of chromosomes in cell division:
mitosis and meiosis
• transcription separated from translation
• sexual reproduction: 2 partners contribute equally to
offspring
• life cycle: alternation of haploid and diploid phases
(i.e. 1 vs. 2 copies of each gene and chromosome)

13. Eukaryotic genomes
 Genetic information is divided in the chromosome.Genetic information is divided in the chromosome.
 The size of genomes is species dependentThe size of genomes is species dependent
 The difference in the size of genome is mainly due to a differentThe difference in the size of genome is mainly due to a different
number of identical sequence of various size arranged in sequencenumber of identical sequence of various size arranged in sequence
 The gene for ribosomal RNAs occur as repetitive sequence andThe gene for ribosomal RNAs occur as repetitive sequence and
together with the genes for some transfer RNAs in several thousandtogether with the genes for some transfer RNAs in several thousand
of copiesof copies
 Structural genes are present in only a few copies, sometimes justStructural genes are present in only a few copies, sometimes just
single copy. Structural genes encoding for structurally andsingle copy. Structural genes encoding for structurally and
functionally related proteins often form a gene familyfunctionally related proteins often form a gene family
 The DNA in the genome is replicated during the interphase ofThe DNA in the genome is replicated during the interphase of
mitosismitosis

14. Eukaryotic Genome

15. Chromosome
 A DNA – histone
protein thread, usually
associated with RNA,
occurring in the nucleus
of a cell
 Chromosomes contain
hundreds of genes
encoded within their
DNA

16. 1616
Chromosome Logical Structure
 Locus
Location of a gene/marker on the chromosome.
 Allele
One variant form of a gene/marker at a
particular locus.
Locus1
Possible Alleles: A1,A2
Locus2
Possible Alleles: B1,B2,B3

17. Gene
 The material that controls which
traits are expressed in an
organism
 Genes come in pairs and
offspring inherit one copy of
each gene from each parent
 A section of DNA that codes
for a trait
 Material of heredity

18.  Genes are pieces of DNA that create proteins:
• located on chromosomes
• inherited from parents
• come in dominant & recessive forms (alleles)
• Ex: Flower color
 Purple allele (dominant)
 White (recessive)
 Letters used to abbreviate alleles
• Dominant Allele = Capital letter
• Recessive Allele = Lowercase letter
Gene

19. Heredity
The passing of traits from parent to offspring

20. The different forms
of a trait that a gene
may have. One
form of a gene
Allele

21.  Ways of looking,
thinking, or being.
 Traits that are genetic
are passed down
through the genes
from parents to
offspring
Traits

22. Recessive
 A trait that is covered over, or dominated, by
another form of that trait and seems to disappear
 Hidden when the other copy of the gene
contains the dominant allele.
 A recessive allele shows up only when there is no
dominant allele present
 Shown with a lower-case letter (a)

23. Dominant
 A trait that covers over, or dominates, another
form of that trait
 Trait that always shows up, even when only one
of the two alleles is in the dominant form
 Shown by a capital letter (A)

24. HomozygousHomozygous
 Both alleles [forms of the gene] are the same
 When offspring inherit two dominant genes, (one
dominant gene from each parent) they are said to
be homozygous dominant (AA)
 When offspring inherit two recessive genes, (one
recessive gene from each parent) they are said to be
homozygous recessive (aa)

25. Heterozygous
 When alleles occur in different forms
 When offspring inherit one dominant gene
and one recessive gene, they are said to be
heterozygous (Aa)
 Since the dominant gene will be expressed,
they are said to be heterozygous dominant
(Aa)

26. GenotypeGenotype
An organism's genetic makeup

27. GenotypeGenotype

28. PHENOTYPE
Outward physical appearance and behavior of an organism

29. What’s the phenotype of a flower that is PP genotype? __________
What’s the phenotype of a flower with Pp genotype? ___________
What’s the phenotype of a flower with a pp genotype? __________
Purple
Purple
White
PHENOTYPE

30. GenesGenes
Segment of DNA which can be transcribed and translated to amino acid

31. Central Dogma of Biology

32. DNA, RNA,
and the Flow of Information
TranslationTranscription
Replication

33. Central Dogma (Modifications)
Transcription Translation
DNA
(1) Reverse
transcription
Replication
RNA
(2)Self Replication
Protein
(3)Self Replication
(2)Ribozymes

34. DNA as Genetic MaterialDNA as Genetic Material
 DNA encodes all the information in the cell
 The composition of the DNA is the same in all cells within an
organism
• Variation among different cells is achieved by reading the DNA
differently
 DNA contains four bases that encode all the information to
make an organism’s life

35. RIBO NUCLEIC ACIDRIBO NUCLEIC ACID
 A polymer composed of nucleotides that contain
the sugar ribose and one of the four bases cytosine,
adenine, guanine and uracile
 Polynucleotide containing ribose sugar and uracile
instead of thymine
 Primary agent for transferring information from
the genome to the protein synthetic machinery

36. Types of RNATypes of RNA
Three types of RNA:
a) messenger RNA (mRNA)
b) transfer RNA (tRNA)
c) ribosome RNA (rRNA)
 Remember:
All produced in the nucleus

37. Codon
 There are 20 different
possible amino acids to
make from different
codons
 Amino acids:
the building of protein
 3 possible stop codon
 1 start codon
TAC on DNA
AUG on RNA

38. Gene ExpressionGene Expression
Production of proteins requires two steps:
Transcription involves an enzyme (RNA polymerase) making an
RNA copy of part of one DNA strand.
There are four main classes of RNA:
i. Messenger RNAs (mRNA), which specify the amino acid sequence of a
protein by using codons of the genetic code.
ii. Transfer RNAs (tRNA).
iii. Ribosomal RNAs (rRNA).
Translation converts the information in mRNA into the amino
acid sequence of a protein using ribosomes, large complexes of
rRNAs and proteins.

39. Steps of gene expressionSteps of gene expression
 Transcription –
DNA is read to make
a mRNA in the
nucleus of cells
 Translation –
Reading the mRNA
to make a protein in
the cytoplasm

40. Poly-peptidePoly-peptide
 A primary structure of a protein
 A sequence of amino acid bonded together by peptide
bonds.
aa1
aa2 aa3 aa4
aa5
aa200
aa199

41. ProteinProtein
 A polymer of amino acids which may consists of one
or more polypeptide chains
 Protein may be water insoluble and serve a structural
role or be water soluble with catalytic activity

42. INTRODUCTION TO GENETICSINTRODUCTION TO GENETICS
 Genetics Concept
 History of Genetics
 Mendel’s Principles
 Meiosis + mitosis
 Linkage and Chromosome Mapping
 DNA as a Genetics Materials and Central Dogma of Biology
 Gene Regulation
 Sex determination
 Genetics of Quantitative Traits

43. Grading system
Grade : 0 – 100
 A > 80
 B – D → 45 – 80 (Normal distribution)
 E < 45
Grade composition
Home work : 30
Mid-term : 30
Final Exam : 40