cline

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cline

(klīn),
A systematic relation between location and the frequencies of alleles; lines connecting points of equal frequency are termed isoclines, and the direction of the cline at any point is at right angles to an isocline.
[G. klinō, to slope]

cline

(klīn)
n.
A gradual change in a character or feature across the distributional range of a species or population, usually correlated with an environmental or geographic transition.

clin′al (klī′nəl) adj.

cline

a gradual and continuous (or nearly continuous) change in a character (such as size or colour) in relation to its geographical or ecological distribution. For example, there is an increase in the percentage of bridled forms in the guillemot population with more northerly latitudes.
References in periodicals archive ?
Clinal variation at aspartate aminotransferase-2 in spotted seatrout, Cynoscion nebulosus (Cuvier), inhabiting the northwestern Gulf of Mexico.
Although the authors noted some latitudinal clinal effects on number of body and tail blotches, they pointed out that 17% of the variation noted in the first character and 10% in the second character could not be explained by those effects.
Males average slightly larger than females, but Pyle (1997) describes the variation as "broadly clinal and obscured by individual variation.
Sackett (2002) reported clinal distribution of mitochondrial 16S haplotypes in Pamlico Sound, NC, and Rose et al.
This potentially allows clinal variation to develop in each valley, adding to spatially variable selective pressures.
The information on geographic variation in litter size suggests that there is no clinal latitudinal variation in neonate size in N.
Although the Eastern Screech-Owl is a textbook example of clinal variation in color-morph ratio (Gill 2007), the pattern is known only at a very coarse scale (Owen 1963a).
On the average, parasite distributional patterns along a stretch of coastline were more often clinal in nature in mytilids, in that prevalence and infection intensity tended to change gradually over relatively large distance scales, and more bounded in nature in oysters, in that prevalence and infection intensity tended to change more sharply over shorter distance scales.
To cite a few examples, Parsons (1993a, 1993b) and Carlson and Parsons (1997) found a clinal variation in reproduction and age and growth among populations of bonnethead sharks from the eastern Gulf of Mexico; Wintner and Cliff (1995) found that size at maturity differed greatly between blacktip sharks from South Africa and the Gulf of Mexico; and Mollet et al.
This frequency is, moreover, clinal in distribution with its highest values in Greece and in the Balkans, decreasing to near-0% frequencies in northwestern Europe where indigenous Mesolithic cultures are most likely to have adopted agro-pastoral techniques.
Most important is the fact that clinal variation in both body and tail blotches cannot account for these taxonomic differences (Table 2).