Chromosomal evolution within the family Estrildidae (Aves) II. The Lonchurae

Abstract

Thirteen species of estrildid finches belonging to the Lonchurae were examined cytogenetically by G-and C-banding. The major forms of karyotypic change, both within and between species, were pericentric inversions and changes in the amount of heterochromatin. It appears that the direction of chromosome change in this lineage is towards an entirely telocentric karyotype because inversions converting a biarmed chromosome into a telocentric one only occur when all the macrochromosomes of smaller size are also telocentric. A comparison of hybrid fertility data and karyotypic differences indicates that genic factors affecting gonadal development, and not chromosomal rearrangements, are the primary influence in determining hybrid fertility. The chromosomal data was also used to clarify systematic relationships within the Lonchurae and demonstrate that the genus Lonchura as presently construed is polyphyletic.

Heterologous Synapsis and Crossover Suppression in Heterozygotes for a Pericentric Inversion in the Zebra Finch

“…Figure 1 D is a schematic illustration interpreting this variant pair 6 with the straight lines representing the lateral elements corresponding to 1 acrocentric and 1 submetacentric chromosome and their respective centromeric signals (green) at the average location according to SC measurements. Previous studies using mitotic spreads defined pair 6 as telocentric, because of the presence of a negligible short arm [Christidis, 1986;Itoh and Arnold, 2005]. We prefer to use the term acrocentric because a very short SC arm is observed with electron microscopy and SMC3 labeling [Pigozzi and Solari, 1998;Calderón and Pigozzi, 2006; this report].…”

“…In this species, the existence of a polymorphism for a putative pericentric inversion in autosome No. 6 was described in wild birds and also in a colony kept for research purposes [Christidis, 1986;Itoh and Arnold, 2005]. As a consequence of this rearrangement, this chromosome exists in 2 alternative morphs: one submetacentric and the other acrocentric.…”

Karyological study of four Indian birds

“…The 2n number has been recorded to be 78 in the present study, in contrast to 80 reported by RAY-CHAUDHURY (1976) but is in conformity with the chromosome number of other confamilial species (BuLATOVA 1981) which ranges from 78-82. The karyotype of E. amandava amandava resembles a confamilial species Lonchura bicolor (CHRISTIDIS 1986) possessing 6 pairs of biarmed chromosomes. The karyotype also shows overall similarity with the karyotype of other confamilial species.…”

Linkage mapping of a polymorphic plumage locus associated with intermorph incompatibility in the Gouldian finch (Erythrura gouldiae)

“…An estimation based on karyotypic banding patterns over part of this phylogenetic branch suggest that an inversion has been fixed every 2.26 My in the estrildid finches (Hooper and Price, 2015). Within the genus Erythrura, for example, the blue-faced parrotfinch (Erythrura trichroa) is separated from GF by two autosomal inversions (Christidis, 1986b;Hooper and Price, 2015). Christidis (1986a) described karyotypic polymorphism in the ZF Z chromosome based on early cytological and banding techniques.…”

“…Recently, Itoh et al (2011) rediscovered these withinspecies genomic rearrangements and mapped the relative positions of some genes by using fluorescent in situ hybridization (FISH) mapping (Itoh et al, 2006(Itoh et al, , 2011, which showed that the current ZF reference genome sequence was based on a submetacentric Z chromosome, whereas an alternative metacentric Z chromosome has been created by an inversion. The Gouldian finch is known to have a submetacentric Z chromosome (Christidis, 1986b). Although it is not possible to determine which marker should be placed at the top of the map using a genetic map alone, our illustration (Figure 1) shows the most likely orientation of the submetacentric Z chromosome of GF under the conventional definition of chromosome arms, with the P5 region belonging to the p arm and P1 region being in the q arm, for the following reasons.…”