ePrints

M-cone opsin gene number does not correlate with variation in L/M-cone sensitivity

Lookup NU author(s): Professor Ted Sharpe

Downloads

Full text for this publication is not currently held within this repository. Alternative links are provided below where available.

Abstract

Molecular genetic studies demonstrate that the human cone opsin gene array on the q-arm of the X-chromosome typically consists of one long-wave-sensitive (L) cone opsin gene and from one to several middle-wave-sensitive (M) cone opsin genes. Although the presence of the single L-cone opsin gene and at least one M-cone opsin gene is essential for normal red-green colour discrimination, the function of the additional M-cone opsin genes is still unclear. To investigate whether any variations in phenotype correlate with differences in the number of M-cone opsin genes, we selected 13 normal trichromat males, for whom four independent molecular techniques have exactly determined their number of M-cone opsin genes, ranging from one to four. Their phenotype was characterized by estimating their foveal L- to M-cone ratio from heterochromatic flicker photometric (HFP) thresholds, by measuring the wavelength corresponding to their 'unique yellow', and by determining their L- and M-cone modulation thresholds (CMTs). No correlation was found between these psychophysical measures and the number of M-cone opsin genes. Although, we found a reasonably good correlation between the L/M-cone ratios based on HFP and on CMT, we did not find any correlation between the estimated L/M-cone ratios and the settings of 'unique yellow'. Our results accord with previous molecular genetic studies that suggest that only the first two genes in the X-linked opsin gene array are expressed. © 2002 Published by Elsevier Science Ltd.

Publication metadata

Author(s): Knau H, Kremers J, Schmidt H-J, Wolf S, Wissinger B, Sharpe LT

Publication type: Article

Publication status: Published

Journal: Vision Research

Year: 2002

Volume: 42

Issue: 15

Pages: 1888-1896

ISSN (print): 0042-6989

ISSN (electronic): 1878-5646

Publisher: Pergamon

URL: http://dx.doi.org/10.1016/S0042-6989(02)00054-8

DOI: 10.1016/S0042-6989(02)00054-8

PubMed id: 12128019

Altmetrics

Share