Chapter 1 & 2 Flashcards
Dna is encoded as a specific sequence of letters along the length of a molecule
Each unit of information is discrete (one of 4 letters in the dna alphabet)
Dna is one-dimensional and digital
Genes
Dna that encodes protein or a particular type of rna
Basic units of biological information (heredity)
Chromosomes
Organized structures containing dna and proteins that package and manage the storage, duplication, expression & evolution of Dna
Genome
Dna within the entire collection of chromosomes in each cell
Organisms change over time
Move
Adapt
Use sources of energy and matter to grow
Metabolism
Large polymers composed of hundreds to thousands of amino acid subunits in long chains
Proteins
20 amino acid’s order determines protein
Amino acid
Basic amino group
& acidic hydroxyl group
Rna
Adenine, uracil.
Uricil replaces thiamine, Less stable than dNA less diverse than protein so intermediate, Read in triplet, Complementarity to dna. May have been the 1st information processing molecule. Can fold into 3-d and catalyze chemical processes, but do not have the # of subunits (20 in protien) so less capacity and diversity.
Pax6 gene
Main control switch for initiating Eye development in fruit flies and humans (mice and insects 2)
Evolution of new genes
Duplication and divergence
Expressed, protein coding region of a gene,
1% of the genome
Exon or exons
Dna that does not code for a protein
Intron
The evolution of complexity is based on… Page 7 essay question
Hierarchic organization of the information encoded in chromosomes
Gene families and gene super families (immune system)
&
Rapid change of regulatory networks that specify how a gene behaves
How new functions evolve
Gene duplication followed by divergence of copies
Rapid diversification of genomes
Reshuffling of exons
Generates evolutionary change
gene regulation (where and when and to what degree a gene is expressed)
genetic dissection
Inactivate a gene in a model organism and observe the consequences (make a conclusion about the functions of a gene product) knock out nice
Genomics
The entire collection of chromosomes in each cell of an organism, 24 kinds of chromosomes, 30,000 genes
Conditional state arising because a gene interacts with environmental factors that affects the genes activation
Various forms of other genes modify the expression of said gene
Predisposition
Act prohibiting insurance companies and employers from discrimination on the basis of genetic tests
2008 genetic information nondiscrimination act
G-c and a-t base pairing in dan through hydrogen bonds
Complementarity
Dna alphabet
G,C
A,T
Guanine, cytosine
Adenine, thymine
The way genes transmit physiological, anatomical, and behavioral traits from parent to offspring
Heredity
The science of heredity, examination of how organisms pass biological information on to their progeny and how they use it in their lifetimes
Genetics
Inferred genetic laws that allowed him to make verifiable predictions about which traits would appear, disappear and reappear and in which generations
Devised a hypothesis that observable traits are determined by independent units invisible to the naked eye
Gregor Mendel
- Variation is widespread in nature
- Observable variation is essential for following genes from generation to generation
- Variation is not distributed by chance
- Laws apply to all sexually reproducing organisms
Four themes in mendel’s work
Purposeful control over mating by choice of parents for the next generation
Canine lupus familiaris
Artificial selection
Moravian sheep breeders society:
What is inherited?
How is it inherited?
What is the role of chance in heredity?
…Sent Mendel to the university of Vienna
Abbot Cyril napp
One parent contributes most to an offsprings inherited features,
Blended inheritance: parental traits become mixed and forever changed in offspring (wouldn’t see skipped generations if that were true)
Misconceptions about heredity
Chose pisum sativum.
Examined clear cut alternative forms of particular traits.
Collected and perpetuated lines of peas that bred true.
Carefully controlled matings.
He worked with large numbers of plants and made predictions based on models.
Focused on seeds in order to observe many more individuals in a limited space.
What Mendel did differently
Both egg and pollen come from the same plant
Self fertilization as opposed to cross fertilization
No intermediate forms
Discrete traits
Show many intermediate forms
Continuous traits
Produce offspring that carry specific parental traits that remain constant from generation to generation
Pure breeding or true breeding lines
Inbred
Offspring of genetically dissimilar parents
Hybrids
Reversing the traits of male and female parents controlling whether a trait is transmitted via the egg cell Or the sperm
Demonstrates that both parents contribute equally to inheritance
Reciprocal crosses
- Transmission of visible characteristics in pea plants
- Defines unseen but logically deduced units (genes)
- Analyzes the behavior of genes in simple mathematical terms
“Experiments on plant hybrids”
Pure breeding
P1 or parental generation
Progeny of the P1 generation, if p1 were true breeding they should all look like a dominant parent, recessive gene being masked
First filial (F1)
Cross between pure breeding lines that differ in only one trait, reveal the units of inheritance and the law of segregation
Monohybrid crosses (F1)
Progeny of F1 generation (interbreeding), both parental types reappear in a 3:1 ratio (3 dominant, 1 recessive) shows blending is not true.
Second filial generation (F2)
Same characteristic independent of sex
Reciprocal
Evidence that blending had not occurred in the F1 cross
Presence of green peas In The F2 generation (yellow being dominant)
Alternative forms of a single gene
Alleles
Individuals having 2 different alleles for a single trait (F1)
Monohybrids
Specialized cells that carry genes between the generations
Gametes
During the formation of sex cells each gamete receives only one allele for each trait
Segregation
Fertilized egg
Zygote
Two alleles for each trait separate (segregate) during gamete formation and the unite at random (one from each parent) at fertilization
Law of segregation
Shows the kind of gametes produced as well as possible combinations that might occur at fertilization
Punnett square
States the the probability of two of more independent events occurring together is the product (x) of the probabilities that each event will occur by itself
1/2 x 1/2 = 1/4
Product rule
State the the probability of either of 2 mutually exclusive events occouring is the sum (+) of their individual probabilities
1/4+1/4= 1/2 like Yy
Or yellow seeds (F1 progeny), 1/4+1/4+1/4 = 3/4
The sum rule
Yellow F2 peas are of 2 types: pure breeding and hybrids
Conclusion: segregation of dominant and recessive alleles during gamete formation and their random Union at fertilization explained the 3:1 ratios observed when hybrids self fertilized
Mendel’s hypothesis
Actual pair of alleles present in an individual
Genotype
Two copies of the same allele
Homozygous
Homozygote
Genotype with two different alleles
Heterozygous
Heterozygote
A cross to a homozygous recessive individual. To decypher an unknown genotype, mate an individual showing the dominant phenotype with an individual expressing the recessive phenotype
Yy or YY to yy
Testcross
Cross between pure-breeding lines that differ at two genes. Usually something like YYRR x yyrr.
yyrr = 1/4 x 1/4 = 1/16 (product rule, refers to combined Monohybrid crosses).
Reveals the law of independent assortment.
F2 phenotypic ratio of 9:3:3:1 (16 zygotes)
Dihybrid cross
New phenotypic combinations
Recombinant types as opposed to parental types
Shuffling of gene pairs during gamete formation
Independent assortment
During gamete formation, different pairs of alleles segregate independently of each other
The law of independent assortment
Cross between pure-breeding lines that differ at three or more genes. Number of different GAMETES = “2n” where n=# of different genes.
F1
AaBbCcDd -> 2 ^4 = 16 kinds of gametes.
AaBbCcDd x AaBbCcDd -> 16 x 16 = 256 genotypes.
Multihybrid crosses
2n, n ,= to the # of traits
The number of different eggs or sperm
Mating between the F1 progeny of pure breeding parents that differ in more than 3 or more unrelated traits
Multihybrid crosses
2n
The number of different eggs or sperm
Mating between relatives
Consanguineous mating
Family history
Pedigree
Disease Not present at birth but later in life
Late onset genetic trait
Huntington disease
HD, Dominant, vertical pattern, defective Htt protein
Cistic fibrosis
CF, recessive gene, horizontal pattern of inheritance, brothers and sisters may express the disease where parents and grandparents won’t. Heterozygous individuals produce enough CFTP for normal lung function.
Bear a dominant normal Allele that masks the effects of the recessive abnormal one
Heterozygous carrier
At least one parent affected
Shows up in every generation (vertical pattern of inheritance)
Unaffected children can be produced if parents are heterozygous
Dominant trait
Consanguineous mating can cause two unaffected parents to produce affected individuals.
Parents of affected individuals are often unaffected, but heterozygous carriers.
All children should be affected if there are affected parents.
Rare traits show a horizontal pattern of inheritance (may not be seen in previous generations).
May show a vertical pattern of extremely common in the population
Recessive trait
Composed of a sugar, phosphate group, and nitrogenous base
Nucleotide
Primary structure (linear), secondary structure (alpha helixes and beta pleated sheets), tertiary structure (final 3-d structure after folding), quaternary (non-covalent interactions that bind multiple polypeptides into a single larger protien)
Structures of proteins
In the electron transport chain, used to compare gene products in different species to provide evidence of relatedness
Chtochrome c
Affect the location, timing, and level of expression of genes (fly wings - double or single pairs)
Regulatory networks
Combined data collection, analysis, theory to understand heredity. Published “experiments on plant hybrids” in 1866
Gregor Mendel
For every trait there is 2 copies of a unit of inheritance (gene) one maternal and one paternal
Mendel proposes “alleles”
What is the probability that event 1 AND event 2 will occur?
P(1and 2) = probability of event 1 X probability of event 2
Product rule
What is the probability that event 1 OR event 2 will occur?
P(1 or 2) = probability of event 1 + probability of event 2
Sum rule
Observable characteristic
Phenotype
During gamete formation different pairs of alleles segregate independently of each other
The law of Independent assortment
A dominant allele usually determines a _____________ functioning protein where a recessive allele usually does not encode a ____________ protein.
Normally, functional
