The exchangeability of shape

<p>Abstract</p> <p>Background</p> <p>Landmark based geometric morphometrics (GM) allows the quantitative comparison of organismal shapes. When applied to systematics, it is able to score shape changes which often are undetectable by traditional morphological studies and even by classical morphometric approaches. It has thus become a fast and low cost candidate to identify cryptic species. Due to inherent mathematical properties, shape variables derived from one set of coordinates cannot be compared with shape variables derived from another set. Raw coordinates which produce these shape variables could be used for data exchange, however they contain measurement error. The latter may represent a significant obstacle when the objective is to distinguish very similar species.</p> <p>Results</p> <p>We show here that a single user derived dataset produces much less classification error than a multiple one. The question then becomes how to circumvent the lack of exchangeability of shape variables while preserving a single user dataset. A solution to this question could lead to the creation of a relatively fast and inexpensive systematic tool adapted for the recognition of cryptic species.</p> <p>Conclusions</p> <p>To preserve both exchangeability of shape and a single user derived dataset, our suggestion is to create a free access bank of reference images from which one can produce raw coordinates and use them for comparison with external specimens. Thus, we propose an alternative geometric descriptive system that separates 2-D data gathering and analyzes.</p

Association of CYP1A1 A4889G and T6235C polymorphisms with the risk of sporadic breast cancer in Brazilian women

OBJECTIVES:We examined the influence of CYP1A1 A4889G and T6235C polymorphisms on the risk of sporadic breast cancer.METHODS:DNA from 742 sporadic breast cancer patients and 742 controls was analyzed using the polymerase chain reaction, followed by the restriction fragment length polymorphism technique.RESULTS:More patients had the CYP1A1 4889AG+GG genotype compared to controls (29.0% versus 23.2%, p=0.004). The G allele carriers had a 1.50-fold increased risk (95% CI: 1.14-1.97) of sporadic breast cancer compared to the other study participants. The frequency of the 4889AG+GG genotype among the Caucasian patients was higher than in the non-Caucasian patients (30.4% versus 20.2%, p=0.03) and controls (30.4% versus 23.2%, p=0.002). Caucasians and G allele carriers had a 1.61-fold increased risk (95% CI: 1.20-2.15) of sporadic breast cancer compared to other subjects. The CYP1A1 4889AG+GG genotype was more common among patients with a younger median age at first full-term pregnancy than among controls (33.8% versus 23.2%, p=0.001) and subjects whose first full-term pregnancies occurred at an older age (33.8% versus 26.1%, p=0.03). Women with the CYP1A1 4889AG+GG genotype and earlier first full-term pregnancies had a 1.87-fold (95% CI: 1.32-2.67) increased risk of sporadic breast cancer compared to the other study participants. Excess CYP1A1 4889AG+GG (39.8% versus27.1%, p=0.01) and 6235TC+CC (48.4% versus 35.9%, p=0.02) genotypes were also observed in patients with grade I and II tumors compared to patients with grade III tumors and controls (39.8% versus 23.2%, p=0.04; 48.4% versus 38.6%, p=0.04). The G and C allele carriers had a 2.44-fold (95% CI: 1.48-4.02) and 1.67-fold (95% CI: 1.03-2.69) increased risk, respectively, of developing grade I and II tumors compared to other subjects.CONCLUSIONS:The CYP1A1 A4889G and T6235C polymorphisms may alter the risk of sporadic breast cancer in Brazilian women