Biology 2C03 - Midterm 1

Transcription

The synthesis of RNA by RNA polymerase. The RNA is complementary to the strand of DNA that was used as the template for transcription

Allele

A specific form of a gene or genetic locus.

Central Dogma of Biology

Genetic information flows from DNA to RNA (transcription) and RNA to protein (translation).

Translation

The synthesis of a polypeptide using the information in mRNA. Synonym for protein synthesis.

DNA Replication

The process by which DNA is copied by DNA polymerase.

Gene

DNA segment that contains information necessary for proper transcription.

Chromosome

Heritable molecule composed of DNA and protein that typically contains genes.

Antiparallel

Orientation of two strands of nucleic acid in a double-stranded nucleic acid. Each end contains the 5' end of one strand and the 3' end of the other.

Phenotype

The observable characteristics of an organism

Complementary base pair

The two nucleotides on opposite, antiparallel strands of a double-stranded nucleic acid, which are hydrogen bonded to each other.

Nucleic Acid Strand Polarity

The orientation of the nucleotides along a single strand of nucleic acid. One terminates the 3' OH group and the other terminates the 5' PO3 group on th sugar.

Genotype

The genetic makeup of an organism

Natural Selection

Process by which populations and species evolve and diverge through differential rates of survival and reproduction of members that are due to their inherited differences.

Mutation

The process that generates new genetic variety through change to existing alleles.

Modern Synthesis of evolution

The reconciliation of modern genetic analysis with Darwin's theory of evolution by natural selection

Syntenic genes

Genes located on the same chromosome

Homologous recombination

Exchange of genetic information between homologous DNA molecules

Recombinant chromosomes

Also called nonparental. Chromosomes in gametes produced by crossing over between linked genes. Alleles marking each gene are rearranged on chromatids by crossing over

Parental chromosomes

Chromosomes in gametes produced when crossing over does not take place between linked genes. Alleles marking each gene are retained in their initial (parental) configurations.

Genetic linkage mapping

Process for creating maps of genes based on their linkage relationship to other genes

Recombination frequency

The rate of occurrence of recombination between a pair of linked genes. Expressed as the number of recombinants divided by the total number of meioses.

Map Unit

A theoretical unit of distance between linked genes on a chromosome

Three point test cross analysis

A test cross designed to identify genetic linkage between three genes and to provide data for determination of recombination frequency between linked genes

double recombinants

The occurrence of two crossovers between homologous chromosomes in a particular region. May involve two, three, or all four chromatids

Interference

Measured on a zero 1.0 scale, the measurement of the independence of crossovers. Expressed as 1.0 minus the coefficient of coincidence.

coefficient of coincidence

The ratio of the observed number of double recombinants to the number of double recombinants expected to occur by chance

negative interference

Occurring when the coefficient of coincidence is greater than 1.0, the observation of double crossovers than expected between a pair of genes

trihybrid cross

A genetic cross between organisms that are heterozygous for three genes

product rule

The probability of an event requiring the sequential occurrence of two or more contributing events. The probabilities of contributing events are multiplied, and their product is the event in question

sum rule

The probability of an event that can result from two or more equivalent outcomes. The probabilities of

prior probability

A statistical prediction of an outcome before the event. In genetics, the prediction of the possible outcomes of a genetic cross based on mendelian genetics

conditional probability

A probability prediction that is dependent on another previous event having taken place

binomial probability

A probability function using two coefficients, a and b, whose sum equals 1 and whose products predict the probability of events

autosomal inheritance

Hereditary transmission of genes carried on autosomes

sex chromosome

Homologous chromosomes that differ between the sexes. Designated X and Y in species in which females are XX and males XY.

pedigrees

A family tree composed of standard symbols that depicts relationships in successive generations and often displays individual phenotypes

autosomal dominant inheritance

A pattern of hereditary transmission in which the dominant allele of an autosomal gene results in the appearance of the dominant phenotype

autosomal recessive inheritance

A pattern of hereditary transmission in which the recessive allele of an autosomal gene results in the appearance of the recessive phenotype

x-linked recessive

A pattern of inheritance consistent with the transmission of a recessive allele of a gene on the X chromosome.

x-linked dominant

A pattern of inheritance consistent with the transmission of a dominant allele of a gene on the X chromosome.

y-linked inheritance

The exclusively male-to-male transmission of genes on the Y chromosome

pleiotropy

A single gene mutation that affects multiple and seemingly unconnected properties of an organism

gene interaction

Referring to genes that interact with one another due to their participation in the production of a particular product or trait

one gene-one enzyme hypothesis

Proposed by George Beadle and Edward Tatum in 1941, the hypothesis proposing that each gene encodes a specific protein product and controls a distinct function

prototroph

The wild-type strain of a microorganism. Also, any organism that can synthesize its nutrients from inorganic material

auxotroph

A microbe with one or more mutations that prevents its growth on a minimal medium

epistasis

A group of specific patterns of gene interaction in which an allele of one gene modifies or prevents the expression of alleles of another gene

complementary gene interaction

A characteristic ratio (9:7) of phenotypes produced by the interaction of two complementary genes that control a trait

duplicate gene auction

A characteristic ratio (15:1) of phenotypes produced by the interaction of two genes that duplicate each other's action due to genetic redundancy

dominant interaction

A characteristic ratio (9:6:1) of phenotypes produced by the interaction of two genes that control a trait in which the presence of dominant alleles of both genes produces one phenotype, one dominant allele of either gene produces a second phenotype, and organisms with only recessive alleles have a third phenotype

recessive epistasis

A characteristic ratio (9:3:4) of phenotypes produced by the interaction of two genes that control a trait in which alleles of one gene mask or reduce the expression of alleles of a second gene

dominant epistasis

A characteristic ratio (12:3:1) of phenotypes produced by the interaction of two genes that control a trait in which a dominant allele of one gene masks or reduces the expression of alleles of a second gene

dominant suppresion

A characteristic ratio (13:3) of phenotypes produced by the interaction of two genes that control a trait in which the dominant allele of one gene suppresses the expression of the dominant allele of the second gene

Pascal's Triangle

A diagram listing the coefficients of a given binomial expansion in which the binomial expression is expanded n number of times

Chi-square test

A statistical test to compare the observed results of an experiment with the results predicted by chance

P value

In the chi square test, the likelihood that a repeat experiment will produce a result as deviant or more deviant than expected in comparison with the experimental result being tested

degrees of freedom

The number of independent variables in an experiment. In a chi square test, most often the number of outcome class minus 1 (n-1)