Anna K. Jasińska

Repetitive sequences that shape the human transcriptome.

Only a small portion of the total RNA transcribed in human cells becomes mature mRNA and constitutes the human transcriptome, which is context‐dependent and varies with development, physiology and pathology. A small fraction of different repetitive sequences, which make up more than half of the human genome, is retained in mature transcripts and shapes their function. Among them are short interspersed elements (SINEs), of which Alu sequences are most frequent, and simple sequence repeats, which come in many varieties. In this review, we have focused on the structural and functional role of Alu elements and trinucleotide repeats in transcripts.

High frequency of recurrent mutations in BRCA1 and BRCA2 genes in Polish families with breast and ovarian cancer

Germ‐line mutations in BRCA1 and BRCA2 genes result in a significantly increased risk of breast and ovarian cancer. Other genes involved in an increased predisposition to breast cancer include the TP53 gene, mutated in Li‐Fraumeni syndrome. To estimate the frequency of germ‐line mutations in these three genes in Upper Silesia, we have analyzed 47 breast/ovarian cancer families from that region. We found five different disease predisposing mutations in 17 (36%) families. Twelve families (25.5%) carried known BRCA1 mutations (5382insC and C61G), four families (8.5%) carried novel BRCA2 mutations (9631delC and 6886delGAAAA), and one family (2%) harbored novel mutation 1095del8 in the TP53 gene, which is the largest germline deletion in coding sequence of this gene identified thus far. The 5382insC mutation in BRCA1 was found in 11 families and the 9631delC mutation in BRCA2 occurred in three families. These two mutations taken together contribute to 82% of all mutations found in this study, and 30% of the families investigated harbor one of these mutations. The very high frequency of common mutations observed in these families can only be compared to that reported for Ashkenazi Jewish, Icelandic, and Russian high‐risk families. This frequency, however, may not be representative for the entire Polish population. The observed distribution of mutations will favor routine pre‐screening of predisposed families using a simple and cost‐effective test. Hum Mutat 16:482–490, 2000.

Do secondary sexual dimorphism and female intolerance to drought influence the sex ratio and extinction risk of Taxus baccata

Sex ratio and sexual dimorphism were studied in the dioecious tree Taxus baccata. We examined five populations of T. baccata in Poland and Ukraine to identify the differences between male and female individuals. The sex of all individuals, height and diameter, needle length and area, specific leaf area (SLA), the number of stomata rows, stomatal density, and content of carbon and nitrogen were measured to identify the differences between male and female individuals. The relationship between sex ratio and climatic conditions, age and population size were analysed using data collected from the field and the literature. Female trees were shorter than males, but needles of females were longer and had larger area. Although there were no differences among sexes in SLA, nitrogen and carbon concentration, we found a positive correlation between nitrogen concentration and SLA among females. The sex ratio changed with tree height within populations, and taller height classes were biased in favour of males. Regardless of population age, the percentage of females within populations was positively correlated with precipitation. Probably high reproductive effort caused female trees to lose in competition with males, and this loss may also be enhanced by lower drought tolerance in females and could contribute to risk of extinction for T. baccata. The continental geographic range of T. baccata may be restricted by limited occurrence of females, which demand higher water resources than males.

Novel BRCA1 mutations and more frequent intron-20 alteration found among 236 women from Western Poland

Three different novel BRCA1 mutations, five independent cases of the same 12 bp insertion-duplication in intron-20 and two novel rare BRCA1 sequence variants were identified among 122 Polish women with positive, in most cases moderate family history of breast and/or ovarian cancer, 80 controls and 34 unselected breast cancer tissue specimens. All mutations and variants were germline. The 4153 delA frameshift mutation, the Tyr105Cys missense mutation and two cases of the alteration in intron-20 were found in the group of healthy women with positive family history. Two other cases of the intronic insertion were found in unselected controls. Their carriers had no family history of breast or ovarian cancer but other cancers occurred in their families. The 1782 Trp/STOP nonsense mutation and one case of the insertion in intron-20 were first found in tissue specimens of breast cancer patient and breast/ovarian cancer patient, respectively. Their carriers also had no family history of breast or ovarian cancer. The distribution of the insertion in intron-20 in analysed groups and results of RT – PCR experiments suggest a less prominent role for this variant considered earlier a splicing mutation. This study shows also, that more population-oriented research is needed, involving women with less profound or even no family history of breast and ovarian cancer, to better understand the role and significance of different BRCA1 variants and mutations.

Prevalence of BRCA1 founder mutations in western Poland.

The frequency of three BRCA1 founder mutations was examined in a group of Polish breast/ovarian cancer patients and women at increased risk of these cancers based on family history. Among the 15 mutations found (5385‐5386insC, 187‐188delAG, and 4154delA), eight were detected in women with a low or moderate family history. The frequency of the IVS20+48ins12 variant was also analyzed and its distribution within risk groups argues against its involvement in cancer predisposition.

Morphological versus molecular markers to describe variability in Juniperus excelsa subsp. excelsa (Cupressaceae)

This is a large scale investigation of morphological diversity in Juniperus excelsa excelsa. It offers complementary results to those obtained for the same populations using molecular markers. These two approaches are complementary and should be considered together in order to obtain a comprehensive view of the variability of J. excelsa excelsa.

Relationships among Cedrus libani, C. brevifolia and C. atlantica as revealed by the morphological and anatomical needle characters

The main aim of the present study was testing the value of the morphological and anatomical characteristics of the needles in distinguishing Cedrus atlantica, C. libani and C. brevifolia. Nine populations were sampled in their natural habit and 25 characters were used to describe the variation of the brachyblast needles and to analyze the differences between species. The results indicated that morphological and anatomical needle characters provide valuable tools in discrimination of the taxa. The scored differences were statistically significant, as revealed in the Tukey’s t test, discrimination analysis and hierarchical analysis of variation. The results support treating C. libani, C. atlantica and C. brevifolia as independent species.

Morphological differentiation supports the genetic pattern of the geographic structure of Juniperus thurifera (Cupressaceae)

Juniperus thurifera is an important component of woodland communities of dry sites within the West Mediterranean region and is characterised by a strongly disjunctive geographic range. Two subspecies were recognised, subsp. thurifera in Europe and subsp. africana in Africa. The aim of the study was the comparison of phenetic diversity to the pattern of AFLP geographic differentiation of the species described in the literature. The examination of phenetic diversity was based on the biometrical analysis of 17 populations using 12 morphological characters of cone and seed. The differences among populations were analysed using Student’s t test, analysis of discrimination, UPGMA agglomeration and hierarchical analysis of variance. The majority of morphological characters differentiated at a statistically significant level between populations and between J. thurifera subsp. thurifera and subsp. africana. Three groups of populations were detected using multivariate statistical analyses. The first, well separated, is subsp. africana, while the following two concern subsp. thurifera. The morphological differentiation of populations appeared similar to that described on the AFLP. The Gibraltar Straight appeared to be the most important barrier.

Morphological diversity and structure of West Mediterranean Abies species

The aim of this study was the biometrical comparison of Abies pinsapo Boiss., Abies maroccana Trab. and Abies tazaotana Côzar ex Villar from Spain and Morocco. The morphological and anatomical analysis of the needle characters of these firs revealed significant taxonomic differences. The results showed considerable distances between regions and very small differences among the Moroccan fir taxa. The examination of the needles and earlier genetic analysis did not provide evidence for distinguishing A. tazaotana at the species level.

Taxonomic and geographic differentiation of Pinus mugo complex on the needle characteristics

The phenotypic differentiation of Pinus mugo complex was verified using 31 populations of P. mugo sensu stricto, 11 of P. uncinata, five of P. uliginosa, one of the potential hybrids P. uliginosa × P. mugo and three of P. sylvestris, the latter as a control. The 22 morphological and anatomical needle characteristics were measured and statistically examined to describe the taxa and the population within the taxa differentiation. All the taxa of the P. mugo complex differed significantly from P. sylvestris in most of the verified needle characteristics. Within P. mugo complex, populations of P. uncinata were clearly distinguished from P. mugo s. s. The population of potential hybrid origin was the most similar to P. uliginosa. Populations of the latter taxon were strongly differentiated; some of them were closer to P. uncinata, and others to P. mugo s. s. Within the whole sampled data, three geographic groups of populations were detected: the first included P. uncinata and two of P. uliginosa, the second contained East and South Carpathian P. mugo s. s. with the presumed hybrid population, and the third contained all the other populations of P. mugo s. s. and P. uliginosa. Within P. mugo s. s., the Sudetan populations formed a separate group. Pinus uncinata from the Pyrenees reflected a high level of differentiation. The marginal populations of this taxon (Cebollera, Gúdar, Massif Central) also differed from those in the Pyrenees. The phenotypic differentiation of taxa and populations appeared similar to that which was detected based on cpDNA markers.