molecular clockn.

Brit.

/məˌlɛkjᵿlə ˈklɒk/, U.S.

/məˌlɛkjələr ˈklɑk/

Origin: Formed within English, by compounding. Etymons: molecular adj., clock n.¹

Etymology: < molecular adj. + clock n.¹

1. A clock based on the behaviour of individual molecules.

ΚΠ

1965 Science 8 Oct. 173/1 The second of Universal Time..could be realized..by astronomical measurements, mechanical clocks, molecular clocks, oscillating crystals, or atomic clocks.

2. Biology. A regular or consistent molecular phenomenon that enables the rate of a process to be assessed or governs the rate at which it occurs; esp. an assumed or inferred consistency in the rate at which molecular changes accumulate during the evolution of particular proteins (or the genes encoding them), from which the timing of evolutionary events may be estimated; a nucleotide (DNA) or amino-acid sequence whose rate of change has been calibrated, and which can be used to estimate the relative dates of evolutionary divergences.

ΘΚΠ

the world > time > instruments for measuring time > clock > [noun] > other types of clock

watch-clock1592

German clock1598

quarter clocka1631

wheel-clock1671

table clocka1684

month clock1712

astronomical clock1719

musical clock1721

repeater1725

Tompion1727

pulling clock1733

regulator1735

eight-day clock1741

regulator clock1750

French clock1757

repetition clock1765

day clock1766

striker1778

chiming clock1789

cuckoo-clock1789

night clock1823

telltale1827

carriage clock1828

fly-clock1830

steeple clock1830

telltale clock1832

skeleton clock1842

telegraph clock1842

star clock1850

weight-clock1850

prison clock1853

crystal clock1854

pillar scroll top clock1860

sheep's-head clock1872

presentation clock1875

pillar clock1880

stop-clock1881

Waterbury1882

calendar-clock1884

ting-tang clock1884

birdcage clock1886

sheep's head1887

perpetual calendar1892

bracket clock1894

Act of Parliament clock1899

cartel clock1899

banjo-clock1903

master clock1904

lantern clock1913

time clock1919

evolutionary clock1922

lancet clock1922

atomic clock1927

quartz clock1934

clock radio1946

real-time clock1953

organ clock1956

molecular clock1974

travelling clock2014

1965 E. Zuckerkandl & L. Pauling in V. Bryson & H. J. Vogel Evolving Genes & Proteins 148 The changes that occur at a fairly regular over-all rate would be expected to be those that change the functional properties of the molecule relatively little... There may thus exist a molecular evolutionary clock.]

1974 Proc. National Acad. Sci. U.S.A. 71 885/1 I think that the rejection or accumulation of appropriate sequences of residues including a glytaminyl or asparaginyl residue during evolution establishes a molecular clock in each protein molecule. These molecular clocks may serve as timers of development, turnover, and aging in proteins, cells, and organisms.

1975 Systematic Zool. 24 212/2 The model that has been used to calibrate the albumin ‘molecular clock’ is based on two assumptions.

1983 J. R. S. Fincham Genetics xviii. 540 Similar comparisons have been made for a number of other ubiquitous proteins, and it is apparent that some change faster than others... If each protein is a molecular clock, the clocks do not all run at the same rate.

1990 G. B. Curry in D. E. G. Briggs & P. R. Crowther Palaeobiol. ii. i. 95/1 The molecular clock must first be calibrated using sequences from organisms which have well dated divergence events—in effect organisms which have a good fossil record.

1995 J. Shreeve Neandertal Enigma (1996) iii. 58 It was only when Sarich and Wilson used their molecular clock to set the time of divergence of one particular higher primate that the trouble began.

1998 Science 16 Jan. 349 It has been proposed that telomere shortening is the molecular clock that triggers senescence.

This is a new entry (OED Third Edition, September 2002; most recently modified version published online March 2022).

单词	molecular clock
释义	molecular clockn. Brit. /məˌlɛkjᵿlə ˈklɒk/, U.S. /məˌlɛkjələr ˈklɑk/ Origin: Formed within English, by compounding. Etymons: molecular adj., clock n.¹ Etymology: < molecular adj. + clock n.¹ 1. A clock based on the behaviour of individual molecules. ΚΠ 1965 Science 8 Oct. 173/1 The second of Universal Time..could be realized..by astronomical measurements, mechanical clocks, molecular clocks, oscillating crystals, or atomic clocks. 2. Biology. A regular or consistent molecular phenomenon that enables the rate of a process to be assessed or governs the rate at which it occurs; esp. an assumed or inferred consistency in the rate at which molecular changes accumulate during the evolution of particular proteins (or the genes encoding them), from which the timing of evolutionary events may be estimated; a nucleotide (DNA) or amino-acid sequence whose rate of change has been calibrated, and which can be used to estimate the relative dates of evolutionary divergences. ΘΚΠ the world > time > instruments for measuring time > clock > [noun] > other types of clock watch-clock1592 German clock1598 quarter clocka1631 wheel-clock1671 table clocka1684 month clock1712 astronomical clock1719 musical clock1721 repeater1725 Tompion1727 pulling clock1733 regulator1735 eight-day clock1741 regulator clock1750 French clock1757 repetition clock1765 day clock1766 striker1778 chiming clock1789 cuckoo-clock1789 night clock1823 telltale1827 carriage clock1828 fly-clock1830 steeple clock1830 telltale clock1832 skeleton clock1842 telegraph clock1842 star clock1850 weight-clock1850 prison clock1853 crystal clock1854 pillar scroll top clock1860 sheep's-head clock1872 presentation clock1875 pillar clock1880 stop-clock1881 Waterbury1882 calendar-clock1884 ting-tang clock1884 birdcage clock1886 sheep's head1887 perpetual calendar1892 bracket clock1894 Act of Parliament clock1899 cartel clock1899 banjo-clock1903 master clock1904 lantern clock1913 time clock1919 evolutionary clock1922 lancet clock1922 atomic clock1927 quartz clock1934 clock radio1946 real-time clock1953 organ clock1956 molecular clock1974 travelling clock2014 1965 E. Zuckerkandl & L. Pauling in V. Bryson & H. J. Vogel Evolving Genes & Proteins 148 The changes that occur at a fairly regular over-all rate would be expected to be those that change the functional properties of the molecule relatively little... There may thus exist a molecular evolutionary clock.] 1974 Proc. National Acad. Sci. U.S.A. 71 885/1 I think that the rejection or accumulation of appropriate sequences of residues including a glytaminyl or asparaginyl residue during evolution establishes a molecular clock in each protein molecule. These molecular clocks may serve as timers of development, turnover, and aging in proteins, cells, and organisms. 1975 Systematic Zool. 24 212/2 The model that has been used to calibrate the albumin ‘molecular clock’ is based on two assumptions. 1983 J. R. S. Fincham Genetics xviii. 540 Similar comparisons have been made for a number of other ubiquitous proteins, and it is apparent that some change faster than others... If each protein is a molecular clock, the clocks do not all run at the same rate. 1990 G. B. Curry in D. E. G. Briggs & P. R. Crowther Palaeobiol. ii. i. 95/1 The molecular clock must first be calibrated using sequences from organisms which have well dated divergence events—in effect organisms which have a good fossil record. 1995 J. Shreeve Neandertal Enigma (1996) iii. 58 It was only when Sarich and Wilson used their molecular clock to set the time of divergence of one particular higher primate that the trouble began. 1998 Science 16 Jan. 349 It has been proposed that telomere shortening is the molecular clock that triggers senescence. This is a new entry (OED Third Edition, September 2002; most recently modified version published online March 2022). < n.1965
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