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genes whose alleles alter phenotypes produced by the action of other genes
what are modifier genes?
the array of chromosomes in a given cell
what is a karyotype?
describes genes present in only one copy such as those on the X in males
What is hemizygous?
a statistical method for testing the fit between observed and expected results
What is a chi-square test?
short sequence of bases where unwinding of the double helix for replication begins
What is an origin?
the heterozygote resembles neither homozygote
what is incomplete dominance?
an animal cell containing more than one nucleus
What is a syncytium?
condensed X chromosome in XX somatic cells
what is a Barr body?
the ratio of observed double crossovers to expected double crossovers
What is the coefficient of coincidence?
a virus that infects bacteria
What is a bacteriophage?
both parental phenotypes are expressed in F1 hybrids
What is codominance?
pairing of homologous chromosomes
What is synapsis?
cell produced by meiosis that does not become a gamete
What is a polar body?
when two loci (locus: the relative chromosomal location of a gene) recombine in less than 50% of gametes
What is linkage?
Griffith experiment
What is transformation?
the alleles of one gene mask the effects of alleles of another gene
What is epistasis?
site of the closest connection between sister chromatids
What is a centromere?
XXY males
What is Klinefelter syndrome?
one crossover along a chromosome makes a second nearby crossover less likely
What is interference?
Transformation principle
What is Hershey-Chase
one gene affects more than one trait
What is pleiotropy?
microtubule organizing centers at spindle poles
What is a centrosome?
XO females
What is Turner syndrome?
structure formed at the spot where crossing-over occurs between homologs
What is a chiasma?
enzymes involved in controlling DNA supercoiling
What is a topoisomerase?