Question | Answer |
What encodes proteins that accumulate in unfertilized eggs and are needed for embryo developments | signal transduction pathways |
substance whose concentration determines cell fate | maternal effect genes |
substance whose concentration determines cell fates, assign identity to body segments | morphogen |
a gene that plays a role in determining a tissue's identity during development | homeotic genes |
individuals with cells of more than one genotype | segmentation genes |
a tag used to follow proteins in living cells | genetic mosaics |
a DNA binding motif found in certain transcription factors | green fluorescent protein |
a gene is turned on in an inappropriate tissue or at the wrong time | homeodomain |
suppression of gene expression by double stranded RNA | ectopic expression |
when a null allele is dominant to a wild type allele | RNAi |
the fate of early embryonic cells can be altered by the environment | haploinsufficiency |
early embryonic cells ar assigned specific fates | regulative determination |
divide the body into identical units (segments) | mosaic determination |
loss of function mutations are ??? | most common |
loss of function mutations | usually recessive, can alter the amino acid sequence – results in diminished (or no) biochemical activity, can interfere with gene expression (transcription, RNA processing, translation) – results in decreased (or no) expression of a normal protein |
null mutations are??? | complete loss of function - aka knockouts |
null mutation | Knockouts can be made by gene-targeting |
hypomorphic mutations | partial loss-of-function, useful for understanding how one gene functions at multiple times in development, e.g. wingless gene in Drosophila is essential for viability of embryos and for formation of wings in adults |
conditional mutations | loss-of-function only under certain conditions
e.g. Temperature-sensitive mutations |
dominant negative (anti-morphic) alleles (or mutations) | inactive protein expressed from mutant allele reduces the function of normal protein expressed from the wild-type allele
ie: multimeric proteins, or mutant receptor that sequesters a ligand |
gain of function mutations | usually dominant, can produce too much protein, or proteins with new function |
haploinsufficiency | In some genes, one wild-type allele is not sufficient for normal development |
homeodomain | DNA binding domain, interacts with specific sequences in DNA |
phenocopy | a change in phenotype arising from environmental events that mimic the effects of a mutation in a gene - no heritable because they do not result from a change in a gene |
RNAi | suppression of gene expression by double stranded RNA, disrupts gene function without mutations |
ectopic gene expression | a gene is turned on in an inappropriate tissue or at the wrong time, expression of a gene at an abnormal place or time - it occurs outside the cell or tissue where the gene is normally expressed |
epistasis | a gene interaction in which the effects of an allele at one gene hide the effects of alleles at another |
morphogen | substances that define different cell fates in a concentration dependent manner |
juxtacrine factors | signaling factors that complete cell to cell communication in the form of direct contact, ligand is membrane-bound and interacts with a receptor on an adjacent cell |
caudal and hunchback | two maternal transcripts that are distributed evenly throughout the oocyte prior to fertilization in drosophila |
homeodomain | a dna binging motif found in certain transcription factors |
mosaic determination | early embryonic cells are assigned specific fates |
what is this: zygote, multinucleate syncytium, syncytial blastoderm, cellular blastoderm | the early embryonic development of drosophila |
T/F: the construction of genetic mosaics can help determine which cells need to express the gene so that the organism can develop normally | True |
T/F: Maternal mRNA transcripts of the bicoid (bcd) gene are deposited in the anterior portion of the egg in drosophila | True |
paracrine signaling | ligand is secreted and mediates long- range (e.g. hormones) or short-range signals (e.g. Wingless and hedgehog) |