Chimerism quantification (CQ) after sex-matched bone marrow transplantation (BMT) is based on the identification of autosomal differences distinguishable at the chromosomal level, such as variations within constitutive heterochromatin between the recipient and the donor. The probability of finding distinguishable recipient/donor pairs at the karyotypic level depends on the frequency of the chromosome variants or morphs in the population, on whether recipient and donor are related, and if so, their kinship relation. We have developed a population genetics-based method that allows the estimation of the percentage of post-BMT CQ expected to be informative using any autosomal polymorphic marker. This method has been developed for the most common transplant situations, such as sibling-matched recipient/donor pairs, haploidentical related (parental/filial) pairs, and unrelated pairs. The method developed was applied to a polymorphism of the pericentromeric region of chromosome 3. This polymorphism becomes evident after in situ digestion with the restriction endonuclease Sau3A, and can be successfully used for CQ. It has been estimated that approximately 59% of the cases of BMT from unrelated donors, 36% of those from sibling donors, and 42% from parental/filial donors, are expected to be distinguishable for post-BMT CQ using this approach.

Chimerism quantification (CQ) after sex-matched bone marrow transplantation (BMT) is based on the identification of autosomal differences distinguishable at the chromosomal level, such as variations within constitutive heterochromatin between the recipient and the donor. The probability of finding distinguishable recipient/donor pairs at the karyotypic level depends on the frequency of the chromosome variants or morphs in the population, on whether recipient and donor are related, and if so, their kinship relation. We have developed a population genetics-based method that allows the estimation of the percentage of post-BMT CQ expected to be informative using any autosomal polymorphic marker. This method has been developed for the most common transplant situations, such as sibling-matched recipient/donor pairs, haploidentical related (parental/filial) pairs, and unrelated pairs. The method developed was applied to a polymorphism of the pericentromeric region of chromosome 3. This polymorphism becomes evident after in situ digestion with the restriction endonuclease Sau3A, and can be successfully used for CQ. It has been estimated that approximately 59% of the cases of BMT from unrelated donors, 36% of those from sibling donors, and 42% from parental/filial donors, are expected to be distinguishable for post-BMT CQ using this approach.

The grasshopper Chorthippus parallelus (Cp) has two distinct subspecies which meet along the Pyrenees forming a hybrid zone. As Cp is rarely found above 2000 m, the contact between the two subspecies must occur through valleys crossing the Pyrenees perpendicularly or at both ends of the mountain ridge. The contact zones in two valleys have already been studied in detail, Col de Porta-let (Central Pyrenees) and Col de la Quillane (Eastern Pyrenees), and this paper analyses the structure of the contact zone at the western end of the Pyrenees. The study has been carried out using different chromosome markers obtained by C-banding and silver staining, both related to the sex chromosome. Although the structure of this contact zone, analysed using these two markers, is similar to that of the contact zones occurring in other valleys, it is much wider and some remarkable peculiarities in the shapes of the clines have been detected. Additionally, hybrid-related sex chromosome markers detected in Portalet have not been found in the present sample.

Heterochromatic supernumerary segments can modify chiasma distribution in the affected bivalents. A model is developed for quantifying the genetic recombination in populations polymorphic for such segments. This paper describes this model for a monochiasmate bivalent, and its application in different populations of the grasshopper Chorthippus parallelus. The observations suggest that these polymorphic systems have evolutionary implications.