Exam 4 Genetics

Homeotic

________ (selector) genes control what structures are formed in a body segment.

Walter Gehring

________ inserted mouse Pax6 into the genome of a fly in the leg.

Fertilization

________: egg and sperm fuse to form a single totipotent cell- the zygote.

Pax

________ 6 gene was turned on by regulatory factors in fly leg.

Ubx

________ represses genes involved in wing formation.

Flowers

________ develop from a group of undifferentiated cells (floral meristem) Various floral homeotic genes control development of the 4 organs Some of these genes are MADS- box genes- no sequence homology with Hox genes.

Cell fate

________ is specified gradually, from coarse to fine.

Bacteriophages

________ (phages) are viruses that infect bacteria (host)

thoracic segment

3rd ________: normally 1 pair of legs, 1 pair of highly reduced wings for balancing.

Hfr

________ bacteria= high- frequency recombination (special class of F+ cells)

Pair rule genes

________: mutations affect every other segment and eliminate a specific part of the segment.

Transduction

________: phage- mediated bacterial DNA transfer /recombination.

Bacteria

________ must be competent- in ________, transient state during which the cell can bind and internalize exogenous DNA, making transformation possible.

Synpolydactyly

________: rare limb deformity characterized by co- presentation of syndactyly (fusion of digits) and polydactyly (more than typical Number of digits) caused by mutation in HOXD13.

Electroporation

________: an artificial version of transformation using electrical current ot temporarily increase permeability of the bacterial cell membrane.

Cellularization

________: when embryo ________, each cell receives any proteins present in the cytoplasm in Position.

Auxotrophs

________: have lost, through mutation, the ability to synthesize one or more organic components and must be grown on supplemented medium.

Concept of selective plating

Mapping in bacteria: Three different methods All rely on recombination ________.

Outcomes

________: entry of foreign DNA into recipient cell and /or recombination between foreign DNA and its homologous region in recipient chromosome.

Stripes

________ are precursors to segmental body plan Turned on by gap genes; control expression of next set of genes (segment polarity) At least 8 pair- rule genes act to divide embryo into a series of overlapping ________ Embryos homozygous for pair- rule genes lack alternating segments Segment polarity genes: mutations cause defects in a portion of a segment (e.g., wingless)

Bithorax

________ (BX- C) complex: 3 genes specify structures in posterior portion of second Thoracic Segment, entire third thoracic segment, and abdominal segments.

Segmentation genes

________: divide embryo into segments (mutants lethal)

Heterooduplex

________: region that contains 1 host strand and 1 mutant strand, from different sources.

Maternal effect

________: genotype of mother determines embryonic phenotype.

Conjugation

________- bacterial genes are transmitted.

Bacterial sex

________= "conjugation Genetic recombination= replacement, not reciprocal exchange Genetic info from one bacterium is transferred to another.

bicoid

Ex: ________ is a transcription factor and activates gap genes in a concentration- Dependent manner.

Partial diplioid bacterium

________= merozygote Transformation: small pieces of extracellular (exogenous) DNA are taken up by bacterial cell and (often) integrated stably into the chromosome.

Bicoid protein

________ is a transcription factor that activates anterior gap genes.

expression of Hox genes

Abd- A represses limb formation by repressing the gene distal- less (DII) A number of genes that control ________ in Drosophila have been identified.

Fate decisions

Simple fate decisions: Sex determination (binary: two choices) Separation of the germline and soma (also binary) Plants: leaves or flowers Blood stem cells develop into- 20 different cell types ________ are "switches: "patterns of gene expression are usually selected by either /or mechanism.

Lytic cycle

________- because ultimately the host cell is lysed Lysogeny: phage DNA integrates into bacterial genome= (lysogenic cycle) virus= prophage, bacterium= lysogenic Viral DNA passes through the generations.

Cell fate

________ is specified independently along the anterior- posterior axis (head- to- tail) and dorsal- ventral axis.

Bicoid protein

________ translates after fertilization and forms a protein gradient.