F
F+ cell -- A bacterial cell having a fertility (F) factor. Acts as a donor in bacterial conjugation.
F- cell -- A bacterial cell that does not contain a fertility (F) factor. Acts as a recipient in bacterial conjugation.
F factor -- An episome in bacterial cells that confers the ability to act as a donor in conjugation.
F' factor -- A fertility (F) factor that contains a portion of the bacterial chromosome. F1 generation -- First filial generation; the progeny resulting from the first cross in a series.
F2 generation -- Second filial generation; the progeny resulting from a cross of the F1 generation. F pilus -- See pilus.
facultative heterochromatin -- A chromosome or chromosome region that becomes heterochromatic only under certain conditions, e.g., the mammalian X chromosome. familial trait -- A trait transmitted through and expressed by members of a family. fate map -- A diagram or \development fate is known. fertility (F) factor -- See F factor.
filial generations -- See F1 and F2 generations.
fingerprint -- The pattern of ridges and whorls on the tip of a finger. The pattern obtained by enzymatically cleaving a protein or nucleic acid and subjecting the digest to two-dimensional chromatography or electrophoresis. FISH -- See fluorescence in situ hybridization.
Back to top fitness -- A measure of the relative survival and reproductive success of a given individual or genotype.
fixation -- In population genetics, a condition in which all members of a population are homozygous for a given allele.
fluctuation test -- A statistical test developed by Salvadore Luria and Max Delbrück to determine whether bacterial mutations arise spontaneously or are produced in response to selective agents.
fluorescence in situ hybridization (FISH) -- A method of in situ hybridization that utilizes probes labeled with a fluorescent tag, causing the site of hybridization to fluoresce when viewed in ultraviolet light under a microscope.
flush-crash cycle -- A period of rapid population growth followed by a drastic reduction in population size. fmet -- See formylmethionine.
folded-fiber model -- A model of eukaryotic chromosome organization in which each sister chromatid consists of a single fiber, composed of double-stranded DNA and protein, which is wound up like a tightly coiled skein of yarn.
footprinting -- A technique for identifying a DNA sequence that binds to a particular protein, based on the idea that the phosphodiester bonds in the region covered by the protein are protected from digestion by deoxyribonucleases.
formylmethionine (fmet) -- A molecule derived from the amino acid methionine by attachment of a formyl group to its terminal amino group. This is the first amino acid inserted in all bacterial polypeptides. Also known as N - formyl methionine. founder effect -- A form of genetic drift. The establishment of a population by a small number of individuals whose genotypes carry only a fraction of the different kinds of alleles in the parental population.
fragile site -- A heritable gap or nonstaining region of a chromosome that can be induced to generate chromosome breaks.
fragile X syndrome -- A genetic disorder caused by the expansion of a CGG trinucleotide repeat and a fragile site at Xq27.3, within the FMR-1 gene.
frameshift mutation -- A mutational event leading to the insertion of one or more base pairs in a gene, shifting the codon reading frame in all codons following the mutational site.
fraternal twins -- See dizygotic twins.
F cell F细胞：E．coli K菌株中无F因子的细胞。 F+ cell F+细胞：E．coli K菌株中具有F因子的细胞。
F factor F因子：即可育因子(fertility factor)，是细菌的一种附加因子，它的存在使宿主具
有供体的能力。
F' factor F’因子：在F因子上带有宿主的染色体片段，因此可将特定的基因以很高的频率
——
传递给受体，产生性导。
Fl generation 杂种1代：由两个基因型不同的亲本杂交产生的第一代杂种。 F2 generation 杂种2代：由F1自交或互交产生的第二代杂种。
F-pili(sex pili) F伞毛(性伞毛)：是F+细胞中的F因子合成的一种很细的管状蛋白，位于细
——
胞表面，可使F+和F或Hfr品系和F细胞彼此连接。
Facultative heterochromatin 兼性异染色质：某些染色质在某一时期或特定的条件下会发生
凝聚而失活，但它本身是含有基因的，如雌性哺乳动物两个x染色体中的一个X染色体部分失活。
Familial trait 家族性状：由一个家族的成员显示出的性状，有的是遗传的，有的是环境造
成的，如饮食造成的肥胖。 fine-structure mapping 精细结构作图：由Benzer．S建立的在一个基因内部不同等位位点之
间的高分辨作图。 ，
first law 第一定律(孟德尔的分离律)在配子形成时成对的等位基因彼此分离，并独立地分配
到不同的性细胞中。
fitness 适合度：在一定的环境中一种基因型的相对繁殖能力。
Fixed breakage point 固定断裂点：根据异源DNA重组模型，DNA双螺旋从这一位点开始
解旋，作为形成异源DNA的开头。
Fluctuation test 波动检测法：一种用于检测微生物随机突变的性质或计算突变率的方法。 Formyl methonine(fMet) 甲酰甲硫氨酸：一种在甲硫氨酸上加上甲酰基的特殊修饰氨基酸，
是原核生物和真核生物细胞器中多肽合成的第一个氨基酸，合成开始后，在有些多肽中被切除。
Forword mutation 正向突变：由野生型等位基因突变为突变型等位基因。
frame-shift mutation 移码突变：由于碱基对的缺失或插入导致了翻译读框的改变，从而产
生完全不同的产物。
fraternal(chizygotic) twin 异卵双生子：由两个卵同时受精产生的双生子，他们的遗传背景
是不同的。
Frequency distribution 频率分布：在群体中各种表型个体所占的比例。
Fruiting body 子实体(孢子果)：真菌的一种器官，在其中发生减数分裂和产生有性孢子。
遗传学名词解释F
