Shnaf A S M Abu, Al-Khalifa M S
Minia University, Faculty of Science, Department of Zoology and Entomology, Minia, Egypt.
King Saud University, College of Science, Department of Zoology, Riyadh, Saudi Arabia.
Braz J Biol. 2021 Sep 15;83:e248814. doi: 10.1590/1519-6984.248814. eCollection 2021.
The karyotype and constitutive heterochromatin pattern of the white stork Ciconia ciconia samples obtained from Manzala lake, Dimiaat, Egypt was described. Somatic cells of Ciconia ciconia samples have diploid number 2n= 68 chromosomes. Out of 68 chromosomes, 11 pairs including sex chromosomes were macrochromosomes and the remaining pairs were microchromosomes. Of the 11 macrochromosome pairs, no.1, 2, 4 and 5 were submetacentric and pairs no. 6, 7 and 8 were described as metacentric. In addition, the autosome pair no.3 was subtelocentric, while autosome pair no.9 was acrocentric. Also, the sex chromosome Z represents the fourth one in size and it was classified as submetacentric while, W chromosome appeared as medium size and was acrocentric. Furthermore, C-banding pattern (constitutive heterochromatin) revealed variation in their sizes and occurrence between macrochromosomes. Pairs no. 7 and 8 of autosomes exhibited unusual distribution of heterochromatin, where they appeared as entirely heterochromatic. This may be related to the origin of sex chromosomes Z and W. However, there is no sufficient evidence illustrate the appearance of entirely heterochromatic autosomes. Therefore, there is no available cytogenetic literature that describes the C-banding and karyotype of Ciconia Ciconia, so the results herein are important and may assist in cytogenetic study and evolutionary pattern of Ciconiiformes.
描述了从埃及迪米亚特的曼扎拉湖采集的白鹳样本的核型和组成型异染色质模式。白鹳样本的体细胞具有二倍体数2n = 68条染色体。在68条染色体中，包括性染色体在内的11对为大染色体，其余为小染色体。在11对大染色体中，第1、2、4和5对为亚中着丝粒染色体，第6、7和8对被描述为中着丝粒染色体。此外，常染色体第3对为近端着丝粒染色体，而常染色体第9对为端着丝粒染色体。同样，性染色体Z在大小上位列第四，被归类为亚中着丝粒染色体，而W染色体呈中等大小，为端着丝粒染色体。此外，C带模式（组成型异染色质）显示大染色体之间在大小和出现情况上存在差异。常染色体第7和8对表现出异染色质的异常分布，它们完全呈现为异染色质。这可能与性染色体Z和W的起源有关。然而，没有足够的证据说明完全异染色质常染色体的出现。因此，目前没有可用的细胞遗传学文献描述白鹳的C带和核型，所以本文的结果很重要，可能有助于对白鹳目进行细胞遗传学研究和进化模式研究。
