Mod 1-4 Flashcards
8 Branches of Genetics
Behavioral Genetics, Biochemical Genetics, Cytogenetics, Developmental Genetics, Evolutionary Genetics, Molecular Genetics, Population Genetics, Quantitative Genetics
5 Applications of Genetics
Plant, Animal, and Microbial Improvement, Medicine, Legal Counselling, Legal Application, Genetic Engineering
The term Genetics was coined by who in 1905
William Bateson
The Greek word ‘gen’ means
“to become” or “to grow into something”
Branch of Biology that deals with heredity and variation
Genetics
Refers to the transmission of traits from parents to offspring. It provides the basis for similarities.
Heredity
Refers to the differences among individuals
Variation
Most fascinating field of Biology
Genetics
The principal determinants of life processes
Genes
A unifying principle in Biology.
Genetics
Three inter-related but broad fields of genetics
Transmission genetics, molecular genetics, population genetics
Also knows as “Classical Genetics”
Transmission genetics
This subdivision of genetics covers the basic principles of genetics (connection between heredity and chromosomes, location and arrangement of gene in a chromosome, gene maping)
Transmission genetics
The focus of this field is on the individual organism from acquisition of traits, genetic make-up, and how it passes on its genes to the next generation
Transmission Genetics
This field delves into the chemical nature of the gene
Molecular Genetics
Molecular genetics revolve around the central cellular processes namely:
Replication, transcription, translation
This field is concerned with studies that describe genetic changes over time and how genetic composition and population dynamics implicate evolution
Population genetics
It (the field) focuses on genetic makeup of individuals of the SAME SPECIES
Population genetics
Studies chromosomes, the visible carriers of DNA
Cytogenetics
Studies how heredity and environmental influences affect behavior
Behavioral Genetics
Studies how genetic variation leads to speciation and adaptation
Evolutionary Genetics
Studies the changes in genes and allele frequencies in populations over space and time
Population Genetics
Studies how genes control the growth and development of an organism
Developmental Genetics
Studies the relationship of genes and their control over functions of an enzyme in a metabolic pathway
Biochemical Genetics
Studies the role of genetics and the environment on inheritance of quantitative traits
Quantitative Genetics
Studies structure and function of genes at a molecular level
Molecular Genetics
The Father of Genetics
Gregor Mendel
Discovered hereditary “factors” which we now refer to as GENES
Gregor Mendel
Observed and predicted transmission of traits across generations
Gregor Mendel
Conclusion of Gregor Mendel
(1) gene is passed from parents to successive generations in a predictable fashion
(2) gene codes for information that would determine structure, function, and other biological properties
Prior to Mendel’s time, heredity was thought to be
a “blending” process
What hypothesis cannot account for cases when children resembled only one of the parents
Blending
Theory that says all organisms originated from miniature forms of themselves
Preformation theory
the pre-formed small human body that can be found in either ovum or sperm
homunculus
Greek philosopher that rejected the notion that offspring is pre-formed in either the “seed (or homunculus)” of ovum and sperm.
Aristotle
For types of causes for existence
Material, Final, Formal, Efficient causes
He proposed that semen was formed everywhere. He referred to a female’s menstrual blood as female semen
Aristotle
According to Aristotle, the male parent provided the
nature of individual
According to Aristotle, the female parent provided the
supportive environment
Formal cause begins the
Developmental process
According to Aristotle, what is the conveyor of inheritance
Blood or semen
Proponent of Theory of Pangenesis
Charles Darwin
Pan from Pangenesis means?
whole
Genesis from Pangenesis means
origin
He discussed his mechanism of heredity through
gemmules
unit of inheritance according to Darwin
gemmules
gemmules is a diminutive word of
gemma
gemma means
bud
minute particles that are shed by cells of an organism
gemmules
What completed theory of evolution
Pangenesis
Theory of Evolution has been widely accepted while Theory of Genesis is largely thought as
wrong
Basis of Pangenesis
Theory of Inheritance of Acquired Characteristics
Proposed to be the fundamental mechanism of evolution
Theory of Inheritance of Acquired Characteristics
It states that as an organism adapt to its environment, modifications to the organisms will arise. Such modifications are automatically handed down to descendants.
Theory of Inheritance of Acquired Characteristics
Theory of Inheritance of Acquired Characteristics
Jean Baptiste de Lamarck
Proponent of Germplasm Theory
August Weismann
Sex cells (or germplasm) perpetuated during reproduction generation after generation
Germplasm Theory
Second most notable evolutionary theorist after darwin
August Weismann
Theory that illustrated how gametes (germ cells - sperm cells or sperm cells) but not somatic cells function as agents of heredity
Germplasm Theory
During what does idantss of germplasm in the zygote doubles
amphimixis
basis or foundation of Classical or Transmission Genetics
Blending
Other scientists who studied Biological inheritance
Naudin, Gartner, Kolreuter, Dzierzon
One scientist who also took into account numerical rations in their methodologies
Dzierzon
Rediscoverers of Mendel
Hugo de Vries (Netherlands)
Erick von Tschermak (Austria)
Carl Correns (Germany)
Showed Mendel’s Principles also apply to animals, not just plants
William Bateson
Edith Rebecca Saunders
Lucien Cuenot
Associated Mendelian factors to physical structures we call ‘chromosomes’
Walter S. Sutton (USA)
Theodor Boveri (Germany)
Confirmed association of genes and chromosomes and demonstrated that MANY GENES ARE HOUSED IN EACH OF THE CHROMOSOMES
Thomas Hunt Morgan
Calvin B. Bridges
what played roles in the structure, function, and evolution of all organisms
genes
Who identified that DNA is the genetic material
Oswald T. Avery
Collin M. Macleod
Maclyn McCarty
Who identified that DNA is the genetic material
Oswald T. Avery
Collin M. Macleod
Maclyn MacCarty
Responsible for the elucidation of the molecular structure of the DNA (DNA Double Helix)
James D. Watson
Francis H.C. Crick
X-ray diffraction and crystallography of DNA
Maurice Wilkins
Rosalind Franklin
Gave better understanding of how genes are transmitted across generations and how they are expressed in individuals or in a population
Crystallography of DNA
Rapid progress in MOLECULAR GENETICS gave rise to disciplines such as
Molecular Biology
Synthetic Biology
Requires knowledge of Mathematics, Statistics, Biochemistry, and Ecology, among others TO ESTABLISH ORDERLY VARIETY OF PATTERNS of patterns and changes in living forms over time
Evolutionary genetics
Need staining technologies, applied physics, advanced microscopy, and imaging techniques to be able to address problems concerning INDIVIDUAL ABNORMALITIES
Cytogenetics
Employ knowledge of Ecology, Math, or Statistics
Population Genetics
Asses population dynamics and the changes in gene and allele frequencies
Quantitative Genetics
Utilize learnings from physiology, morpho-anatomy, and biochemistry to explain how individuals of THE SAME OR DIFF SPECIES WOULD DEVELOP and HOW THEY MAINTAIN THEIR OWN UNIQUE PATTERN AND ABILITY O EXIST CONTINUALLY
Developmental Genetics
Knowledge of inheritance of both desirable and undesirable characterstics in family
Genetic counselling
DNA profiles or fingerprints
Legal application
Greater opportunities to realize genetic gain, stable increases, and better production
Recombinant DNA Technology
Improving crops, domestic animals, and microorganisms
Selective Hybridization and breeding
Basic unit of life
Cell
genetic material in nuclear zone is also referred to as
nucleoid
genetic material in nuclear zone not enclosed in distinct bound nucleus and freely suspended in cytoplasm
Prokaryotic cell
Contain intracellular membranes, a true nucleus, and intracellular compartments
Eukaryotic cells
intracellular components are also known as
organelles
Genetiic material is in the form of
Chromatin
Compact form of chromatin
chromosome
housed within the nucleus, separated from the cytoplasm by a nuclear membrain
chromosome
conspicuous domain in nucleus which serve as a site for producing and assembling the cell’s ribosomes
Nucleolus
Sample of Prokaryotic cell
Bacteria
Cyanobacteria
Sample of Eukaryotic cell
Protist
Fungi
Plants
Animals
Size of prokaryotic cell
1-10 um
Size of eukaryotic cell
10-100 um
Cell division of Prokaryotic cell
Binary fission
Cell division of Eukaryotic cell
Mitosis and Meiosis
a double-membrane structure that is the primary director of cellular activity and inheritance
nucleus
dark network of nuclear content
chromatin
chromatin is stored in
nucleus
during cell division, chromatin become distinct bodies called
chromosomes
series of events where cell grows and divides
cell cycle
preparatory and non-dividing stage of cell cycle that precedes cell division
Interphase
cell division is also known as
M-Phase (Mitosis/Meiosis)
What stage is consisted of morphologically identical but biochemically distinguishable phases
Interphase
re the biochemically distinguishable phases
G1
S
G2
Longest phase in cell cycle. During this, cell imbibes water and nutrients and builds new protoplasm and cytoplasmic organelles
G1 phase
Synthesis stage considered of prime importance because it is during this period when DNA is replicated
S phase
Period when cell synthesizes RNA and proteins
G2
What happens at the end of G2
Cell is ready to divide
Genetic Material is duplicated
Double chromatin fiber is folded to become chromosome
Contents of octameric histone core
2 each of H2A, H2B, H3, and H4 histones
DNA wrapped around octameric histone core form a blank that spans a diameter of 11 nm
nucleosome
What stabilize the linking of DNA to the core which forms Chromatosome
H1 Histone
Nucleosomes are coiled in the form of a
solenoid
any nucleosomes per coil
6
What is the diameter of chromatin thread formed by solenoidf
30 nm
each chromosome is composed of how many sister chromatids
2 sister chromatids
Kinetochore proteins attach to Blank which is also known as the primary constriction
Centromere
What attaches to kinetochore proteins
Spindle fiber
The tips or ends of chromosomes are referred to as
Telomeres
Secondary constriction which looks like a knob structure at terminal portion
Saellite
complete set of genes or chromosomes coming from male or female parent is called
Genome, denoted by X (basic chromosome number)
True diploid (X) is equal to
haploid number (n)
diploid number is also referred to as
Somatic chromosome number (2n)
Haploid number is also called as the
gametic chromosome number (n)
What consist the 24 hour cell cycle of humans
8 hours G1 Phase
11 hours S-phase
4 hours G2-phase
1 hour M-phase
Mitosis for unicellular organisms is to
to reproduce
Mitosis for multicellular organism is for
for growth and development
for replacement of damaged cells
The first to note and describe in detail how chromosomes move during mitosis, which helped Sutton and Boveri’s Chromosomal Theory of Inheritance
Walter Flemming
Stage where chromosomes condense and are visible composed of sister chromatids
Prophase
Spindle fibers attached to kinetochore align the chromosomes at the equitorial plate
Metaphase
Sister chromatids are pulled apart and moved to the opposite poles by “shortening” (depolymerization) of spindle fibers. Each sister chromatid = 1 chromosome
Anaphase
Chromosomes reached the opposite poles and form two groups having the same number of chromosomes.
Telophase
ision of cytoplasm that is achieved after telophase
Cytokenesis
Plant cells forms what at metaphase plate
phragmoplasts (cell plate formation)
Animal cells forms what at metaphase plate
cell cleavage (cleavage furrow formation)
It involves union of two haploid cells
fertilization
special kind of cell division undergone by germ cells
Meiosis
Process of meiosis was discovered and described independently by
Walter Sutton - grasshopper testes
Theodor Boveri - Worms (Ascarsis Sp.)
Referred to as the reductional division
Meiosis I
Process of meiosis was discovered and described independently by
Walter Sutton - grasshopper testes
Theodor Boveri - Worms (Ascarsis Sp.)
A transitional stage between Meiosis I and II
interkinesis
Equational division are
Mitosis and Meiosis II
5 substages of Prophase I
LZPDD
Leptotene
Zygotene
Pachytene
Diplotene
Diakinesis
This stage is similar to earliest prophase wherein chromosomes appear as thin threads
Leptotene
Homologous chromosomes pair (aka synapsis) and associate bivalents.
Considered as the adjoining phase
Stage where Synaptonemal complex forms between homologous chromosomes
Zygotene
Protein structure that is essential for crossing-over
Synaptonemal complex
Stage where chromatids undergo repair when damaged. This may involve crossing-over facilitated by synaptonemal complex
Formation of chiasma
Pachytene
Point of chromatid exchange at cross-over forms what
Chiasma
Stage where synaptonemal complex loses functionality and bivalents get separated.
Chromosomes shorten and terminalization of chiasma occurs
Diplotene
Stage where chromosomes are contracted, nucleolus disintegrated, and formation of spindle begins.
Best stage to establish chromosome number
Diakinesis
Bivalents arrange at metaphase plate
Metaphase I
Homologous chromosomes separate from each other and move toward opposite poles. Each chromosome is composed of haploid number, ACCOUNTING FOR THE REDUCTIONAL PHASE of Meiosis I
Anapahase I
Chromosomes regroup at the poles. Chromosomes begin to relax. Cytoplasm may divide (cytokinesis) to produce two distinct haploid cells
Telophase I
Chromosomes of TWO haploid cells appear duplicated. Nuclear membrane and nucleolus disintigrate at this stage
Prophase II
wo new spindle fibers are formed. Chromosoimes align at the metaphase plate
Metaphase II
Chromatids separate from each other
Anaphase II
Chromosomes regroup at their arrival pole. It uncoils and lengthen. Nuclear membrane and nucleolus reapper. Cytoplasm gets divided (cytokinesis) to produce a total of four distinct haploid cells
Telophase II
Variations is due mainly to
Differences in time spent for each generation
Type of phase species is predominantly in
Products (gametes or spores)
Also known as Terminal or Gametic Meiosis showed by animals and lower plants
Gametic life cycle
Produced during fertilization of haploid gametes
diploid zygote
Gives rise to primary spermatocytes
spermatogonium
ves rise to primary oocytes
oogonium
Ovum/Sperm carries a haploid set of chromosome ___
(22+X)
Known as the Initial or Zygotic Meiosis exhibited by algae, fungi, and diatoms
Zygotic Life Cycle
Gametic life cycle is type described as
diploid-dominant life cycle
Intermediary or sporic meisos typically shown by flowering plants and those species with alternation of generation is known as
Sporic Life Cycle
Haploid multicellular plants are called
gametophytes (producing gametes and meiosis is not typically involved
Fertilization of gametes from the diploid zygote that will undergo rounds of mitosis and produce a MULTICELLULAR DIPLOID PLANT is called
sporophyte
Scientific name of green peas
Pisum sativum
Inherited factor on chromosome responsible for a trait
gene
location of gene on a chromosome
locus
genetic constitution of an individual
genotype
alternative forms of a gene
allele
physical, physiological, biochemical, and behavioral traits of an individual
phenotype
determined by genotype and its interaction with the environment
phenotype
gene expressing full effect despite the presence of another allele of the same gene
dominant
gene not expressed in presence of another allele
recessive
two copies of the same allele of a gene (e.g. YY, yy)
homozygous
two different alleles of the same gene (e.g. Yy)
heterozygous
cross between two individuals with contrasting traits
hybridization
first generation produced after mating between parents that are homozygous for different alleles
F1 or first filial generation
The generation produced by self fertilization or sib-mating of F1 individuals
F2 generation or second filial generation
crossing of a heterozygote with one of its parents
Backcrossing
(pre-mendelian) thought of a blending process
Heredity
Samples that Mendel used with contrasting traits
Pure line or true breeding parents
one dominant allele is enough to express the dominant trait
(Homozygous or heterozygote have the same phenotype)
Complete Dominance
Alleles in gene pair separate cleanly from each other during meiosis
Law of Segregation
Genotypic ratio of AA x Aa
2 AA : 2 AA or 1 AA : 1 Aa
Genotypic ratio of Aa x aa
2 Aa : 2 aa or 1 Aa : 1aa
consider two traits at the same time
Dihybrid cross
If parentals are RRYY x rryy, what are the Gametes and F1?
Gametes: RR x Ry
F1: RrYy
F2 Ratio of RRYY x rryy
or F1 RrYy
9:3:3:1
Alleles of DIFFERENT GENE PAIRS
SEPARATE INDEPENDENTLY from each other and RANDOMLY COMBINE during meiosis
Law of Independent Assortment
If two pairs of contrasting traits are inherited independently, to predict the frequencies of F2 phenotypes, apply the
Proudct Law of Probabilities
For simultaneous occurence of two independtent events what is equal to the product of their individual probabilities
combined probability of two outcomes
If two events are not independent, the likelihood of an outcome is referred to as
Conditional Probability
He isolated nuclein from nuclei of pus cells
Friedrich Miescher
nucleus required in cell division and fertilization
O. Hertwig
Chromosomes are in the nucleus
E. Strassburger
Walter Fleming
Correlations between Chromosomes and Mendelian Factors
Chromosome and Mendelian Factors exist in pairs
Homologous chromosomes and mendelian factors separate at Anaphase I
Fertilization restores the diploid chromosome Number
F2 phenotypic and genotypic ratio of Complete Dominance
F2 genotypic ratio: 1 AA : 2 Aa : 1 aa
F2 phenotypic ratio: 3:1
F1 phenotype is intermediate
Incomplete dominance
Phenotypic and Genotypic ratio of F2 Incomplete dominance
F2 Genotypic ratio: 1 AA : 2 Aa : 1 aa
F2 Phenotypic ratio : 1 : 2 : 1
Aa is superior to AA and aa (heterosis or hybrid vigor)
Overdominance
products of two alleles in heterozygote are present
Co-dominance
What is present on the surface of RBC
Glycolipid (oligosaccharide + lipid)
Reason behind ABO blood types
difference in oligosaccharide
Genotype of A blood type
AA
AO
Genotype of B blood type
BB
BO
Antigen of O blood type
H
H antigen is
Fucose (5th)
A antigen is
N-acetyl glucosamine (6th)
B-antigen is
galactosamine (6th)
Universal Blood Donator
O
Universal Blood Receiver
AB
genes that can cause death
lethal genes
lethal when homozygous recessive
could result to a recognizable phenotype when heterozygous
Recessive lethal gene
1:2:1 genotype
1:2:0 phenotype
Abnormal spine development
Extreme development abnormality
Causes the death of the embryo
Tailless
Heterozygous
Manx allele (Mn^l)
Homozygous recessive; normal at birth
Deterioration of CNS starts before 1 yr old
Loss of neuromuscular control; blindness
Lack of hexosaminidase A
Accumulation of GM2 gangliosides (lipids in brain and nerve cells)
usually fatal at three to four years old
Tay-Sachs disease
Lacks DNA repair enzyme
Photosensitive
Exposure to light causes freckling and pigmentation and warty growths
Xeroderma pigmentosum
letal when homozygous dominant or heterozygous
Dominant Lethal Gene
The dominant allele codes for an abnormal HUNTINGTIN protein
Described by George Huntington
Progressive degeneration of CNS; involuntary movements
onset of symptoms at 30 y.o. or earlier death at 40-50 y.o.
Huntington’s disease
gene changes phenotypic effect of other genes in a QUANTITATIVE fashion
Dilution or enhancement effect
Modifier genes
Non allelic interaction of two or more genes
result in a modified phenotypic ratio
interaction between two or more genes determine single phenotype
Gene Interaction
interaction of two or more genes
determined by observing certain phenotypic ratios
Epistasis
F2 ratio: 9:3:3:1
E.g. comb type in poultry
Novel phenotype
F2 Ratio: 9:3:4
Homozygous recessive gene hides the effect of the other gene
Recessive Epistasis
F2 Ratio: 12:3:1
Dominant gene masks the expression of the other gene
Dominant Epistasis
One gene when dominant is epistatic to the second
Second gene homozygous recessive is epistatic to the first
F2 ratio: 13:3
Dominant epistasis
Either gene when homozygous recessive is epistatic to the other gene
F2: 9:7
Complementary gene action
Either gene when dominant is epistatic to the other gene
F2: 15:1
Duplicate gene action
Lewis 1951
Star-asteroid in Drosophila
Star and star recessive (ast)
two different mutants located on same chromosomes
Pseudoalleles
Phenotype is not only dependent on genotype but also on the position of the genes on the chromosome
Lewis effect or Position effect
Proportion of genotype that shows the expected phenotype
Penetrance
all will show the trait (100%)
complete penetrance
not all will show the trait
incomplete penetrance
degree in which a particular phgenotypic effect is exhibited by an individual
Expressivity (Constant or Variable)
one gene has multiple phenotypic cell effects (e.g sickle cell anemia)
Pleiotropy
Genetically based human disease
Sickle cell anemia
environmental mimic of gene action
Environmental induces a particular phenotype that resembles a genetically determined phenotype
Phenocopy
drug to cure morning sickness
Thalidomide
Underdeveloped limbs
Phocomelia
Environmental factors responsible for differences in penetrance & expressivity
- External Environmental
a. Temperature
B. Light
C. Nutrition
D. Maternal relations - Internal environment
a. age
b. sex
c. substrates
both members or twins show or dont show the trait
concordant
only one member shows the trait
disconcordant
High heriditary influence results in
High concordance in identical twins
Low concordance in fraternal twins
Low hereditary influence & high environmental influence
Equal concordance and disconcordance between IT and FT
