Biomedical subjects

Frank Y T Sin

Publications and source records attributed to Frank Y T Sin.

3 recordsLinked to original sources

PubMed2006

Isolation, characterization, and expression analysis of three actin genes in the New Zealand black-footed abalone, Haliotis iris.

Three actin genes -- H. irisA1, H. irisA2, and H. irisA3 -- from the mollusc Haliotis iris (New Zealand black-footed abalone) were isolated by polymerase chain reaction (PCR). The genes were similar to molluscan (84.1% to 94.9%) and vertebrate (84.5% to 86.6%) actins. The sequence similarity between the genes ranged from 88.5% to 93.2%. The greatest disparity, 32.3%, was found over a 99-nt region located at nt 808-906 of H. irisA1, corresponding to amino acids 212-244 of the three actins. The H. iris actin gene family contains at least eight members. Reverse transcription (RT)-PCR analysis of the three genes showed H. irisA1 and H. irisA2 were expressed at low levels in fertilized eggs and blastula stages and at high levels in trochophore and veliger larvae. H. irisA3 was detected in fertilized eggs; it was not detected in the blastula stages and at high levels in the trochophore and veliger larvae. The structure and expression of the three actin genes are discussed.

Actins↗

PubMed2003

Absence of association of androgen receptor trinucleotide expansion and poor semen quality.

This study investigated the relationship between variation in the polymorphic CAG trinucleotide repeat (TNR) region of the human androgen receptor (AR) gene and semen quality in a Caucasian sample population. These men were patients attending the New Zealand Centre for Reproductive Medicine in Christchurch. The AR TNR region was amplified by polymerase chain reaction and then DNA sequenced to determine exact numbers of CAG repeats for each sample. In addition, the samples were screened for microdeletions within the AZFc region of the Y-chromosome. A total of 105 men with poor semen quality were compared with a group of 93 men with normal semen quality. Men with poor semen quality had similar CAG repeat number to men with normal semen quality (21.46 +/- 0.30 vs. 20.99 +/- 0.28, p = 0.126). Y-chromosome microdeletions were only detected in men with suboptimal semen parameters (7.4%). However, the presence of a deletion was not related to CAG repeat number. The CAG repeat number in the men with normal semen quality in the present study is similar to the Australian and German samples, but lower than those reported for the Swedes, Dutch and Danes. These results are contrary to the hypothesis that higher CAG repeats are associated with infertility in men, but strongly suggest that different populations may show different numbers of CAG repeats in addition to racial variation reported in previous studies.

Gene Deletion↗

PubMed2002

Mitochondrial mutations may drive Y chromosome evolution.

The human Y chromosome contains very low levels of nucleotide variation. It has been variously hypothesized that this invariance reflects historic reductions in the human male population, a very recent common ancestry, a slow rate of molecular evolution, an inability to evolve adaptively, or frequent selective sweeps acting on genes borne on the Y chromosome. We propose an alternative theory in which human Y chromosome evolution is driven by mutations in the maternally inherited mitochondrial genome, which impair male fertility and ultimately lead to a reduction in the effective population size (N(e)) and consequently the variability of the Y chromosome.

Animals↗