GEF

Reasons why Mendel was successful in understanding heredity 

He used scientific and quantitative methods 

Enclose the flower

Sepals function

Petals

comes in various shapes and colors

Anther

produces pollen

Carpel/pistil

Female reproductive organ

Stigma

pollen deposit

Style

Tube to ovary

Ovary

holds the ovule

Ovule

female gamete

self-pollination

pollen from anther of the same plant to the stigma

cross-pollination

pollen from the anther of another plant to the stigma 

Allele

alternative forms of a gene 

Trait

appearance of a characteristic 

Ratio of phenotype and genotype of monohybrid cross

geno-1:2:1, pheno- 3:1

Ratio of phenotypes in Mendel’s dihybrid cross

pheno- 9:3:3:1

Describe Mendel’s principles of heredity 

Each plant possesses two genetic factors or alleles that encode a trait,  Alleles are separated with equal probability when a plant forms gametes and one allele is present in one gamete à Both alleles cannot be present in a gamete, When 2 gametes fuse to form a zygote, allele from male parent unites with allele from female parent

Explain how meiosis can explain Independent assortment 

In meiosis the there are several combination of possible c’somal arrangements which will alleles to assort independently

Complete Dominance

In heterozygous individuals only one phenotype is detected

Incomplete Dominance

When homozygous individuals do not completely show one phenotype

Codominance

Heterozygous individual display both phenotypes

Penetrance

Probability of phenotype from a genotype 

Incomplete penetrance

When a phenotype shown is not expected of genotype 

Expressivity

Degree to a trait being expressed

Anticipation

Increasing severity of disease or earlier age of onset of a genetic trait in successive generations

Lethal allele

Allele that causes death of the organism

Blood Type of 1. IA I 2. IA IB 3. ii

1. A
2. AB
3. O

Epistatic gene

Gene that Suppresses another gene 

Hypostatic gene 

Gene that is suppressed by epistatic gene

double recessive epistasis 

Two recessive alleles on two different loci repress a phenotype

Sex linked characteristics

characteristics that are determined by genes directly located on sex chromosomes

Sex-Influenced Characteristics

Characteristics that are more likely toward a certain sex, genes are located in autosome

Sexs-limited Characteristics

Trait encoded on autosomes but are expressed only in one sex.

inheritance of mitochondria and chloroplasts 

The male gametes is always degraded leaving only passing of genes from the mother.

cytoplasmic inheritance

Phenotypes displayed are the result of genes of the mitochondria and chloroplast

Maternal effect 

Mothers genotype decides the offspring’s phenotype. Explained by mother placing mRNA and proteins in eggs used in early development

Polygeny

Many genes are involved in deciding a phenotype

Pleiotropy

One gene influences multiple genes 

Multifactorial characteristics 

Phenotypes decided by genes and environment 

Concept of linked genes 

2 Traits that cannot assort independently

When are genes considered linked 

2 genes that are close together on the same C’some 

When does independent assortment occur 

Occurs during Meiosis I

Difference between recombinant and nonrecombinant gametes

If crossing over has happened or not

Cis Configuration

same allele type on one C’some dominant or recessive

Trans Configuration

one dominant and one recessive.

Equation to find distance between 2 genes that are on the same chromosome from the number of progeny obtained

(# of recombinant progeny/ # of total progeny)\* 100 = _______ cM

Difference between a genetic (or chromosomal) and physical map 

Genetic map – tells where genes are on a C’some. Physical Map- tells what genes are on what C’some 

Somatic cell hybridization 

Creates a heterokaryon by fusing a human fibroblast and a mouse tumor cell which will create multiple cells lines with different C’somes and analysis the gene product with the C’somes present will let you know which gene is on which C’some. 

Deletion mapping 

By viewing the karyotype of C’somes with deleted regions it is possible to see if a mutant is there or not in the progeny. 

Heterokaryon

Human fibroblast + Mouse tumor cell 

Two types of DNA sequencing 

Sanger Sequencing, Genome wide sequencing

Test Cross

Cross involving homologous recessive

transposable elements (transposons)

Gene that move within the genome without nonhomologous recombination

Features seen in transposable elements (transposons) 

Terminal inverted repeats at the ends, Flanking direct repeat: next to terminal but not part of the transposon

Locations of terminal inverted repeats, flanking direct repeats, and transposase coding sequence 

Outer Flanking, inverted, coding sequence

Types of transposons

Class I: Retrotransposons

Class II: DNA transposon 

transposition general mechanism

DNA is cut making staggered ends, transposons places itself inside the staggered end, gaps are filled by DNA polymerase and creates the flanking direct repeat

Replicative Transposition

Transcription of transposon forms a RNA intermediate which is converted back into DNA and is transposed

Non-replicative Transposition

DNA is excised and is transposed

The transposon is able to move around when an enzyme is able to cleave it at one location and then cut another piece of DNA at another location where it gets inserted. Name the enzyme that is able to mediate this cutting process. 

Transposase

Regulation of transposition 2 methods

__Methylating DNA__: prevent the transcription of the transpoase.

regulating translation of transposase enzyme

How transposons can influence phenotypes 

Transposons placed upstream of a gene may reduce the expression of the genotype 

How transposons generate mutations within a gene 

places itself inside a gene 

How transposons cause chromosomal rearrangements 

Two transposome in the same orientation = deletion and opposite orientation = insertion 

Definition of epigenetics 

Phenotypes and processes that are transmitted to cells in the future but not by DNA differences

DNA methylation (epigenetic)

Promotes Heretrochromatin production and prevents binding of transcriptional regulators

Histone modifications (epigenetic)

Addition of Acetyl group = reduce trans. Or remove = influences trans.

RNA molecules: long noncoding RNA and small RNA like miRNA and siRNA

siRNA- promotes mRNA degradation, miRNA- inhibits translation, Xist long coding RNA- coat C’somes which recruits methyl transferase 

Chemicals

likes insecticides, alcohol, cigarettes, the fungicide vinclozin mimics testosterone which causes mice to produce less sperm.

Behavior (epigenetic)

rats being groomed by mother = DNA acetylation = braver rats

Monozygotic twins (epigenetics)

will be different due to epigenetic changes

Genomic imprinting

gene expression depends on sex of the parent that provided it.

Gene conflict hypothesis and genomic imprinting in the context of Igf2 and Igf2R 

IGF2 promotes growth and IGF2R counteracts IGF2. IFG2 is expressed when gene is from father. IGF2R is expressed when given from mother. 

Gene conflict hypothesis

since the nutrients is provided by the mother IGF2R makes it so that the children do not over burden the mother. 

Definition of genotypic frequency 

How many people have a certain genotype in a population 

Definition of allelic frequency 

Prevalence of an allele in a population

Hardy-Weinberg law What does the law state 

Allelic frequencies do not change 

What factors affect allelic and genotypic frequencies

mutations, matting patterns, migration, population size, natural selection

Relation between mutation and genetic variation 

Increases genetic variation due to it create alleles 

Types of non-random mating

Positive assorted mating: tendency for like individuals to mate, Negative assorted mating: tenendcy for unlike individuals to mate, inbreeding preference between related individuals 

Relationship of inbreeding and homozygotes 

Inbreeding raises the likelihood of homozygous genotypes

Definition of gene flow

Influx of alleles from a population

Effect of migration on genetic variation 

Increases genetic variance 

How migration influences allelic frequencies

Spreads alleles in a population

Definition of genetic drift 

Random change of the allele frequency 

Causes of genetic drift 

population size, founder effect, bottleneck, fixation 

Definition of Founder effect 

few individuals leave a population make a new population

Definition of Bottleneck effect 

 population undergoes major reduction in size

Definition of fixation

when the allele frequency reaches 1

Relation between genetic drift and genetic variation 

drift reduces the likelihood of genetic variation. 

Definition of natural selection 

Certain adaptive traits promote survival 

Definition of fitness 

reproductive success of a genotype

Types of selection (be able to identify and explain): Disruptive, directional, and stabilizing selection,

Disruptive- advantages trait is either extremely large or small not in the middle, Directional- one extreme is promoted only, Stabilizing- the average of the traits is promoted

Anagenesis

Evolution of a single lineage 

Cladogenesis

Evolution when one lineage splits to 2

Biological species concept’s definition of species 

Group of organisms that care capable of interbreeding but do not breed with other species 

Meaning of reproductive isolation 

Do not breed with other species 

Prezygotic reproductive isolating mechanisms: definition, ways by which the process can occur 

Gametes of 2 species cannot fuse, Ecological- habitat location, behavioral-, Temporal- mating occurs at different times, Mechanical- different reproductive structures, Gametic isolation- Gametes cannot fuse 

Postzygotic reproductive isolating mechanisms: definition, ways by which the process can occur

Gametes can fuse but hybrid is sterile or inviable, Hybrid inviability- zygote does not develop, Hybird sterility-, Hybrid breakdown- fertility drops with further crossing

speciation

Formation of a new species