metacentric
1.A metacentric chromosome.
2.The X chromosome was a metacentric chromosome whose length was between the 8 th and 9 th chromosome, while the Y chromosome was a smallest metacentric chromosome.
3.Thirty six homologous pairs of chromosomes were autosomes , in which chromosomes ,pairs of 1 to 20 were acrocentric-subterminal , 21 to 36 metacentric-submetacentric . And X chromosome was metacentric, Y chromosome terminal.
4.All the 29 homologous pairs ofautosomes and the X chromosome were acrocentric chromosomes. The Ychromosome was submetacentric in Angora goats, and metacentric inNative goats.
5.The karyotypes of the genus Abies (excl. A. forrestii) are composed of metacentric and submetacentric. chromosomes and belong to 2A type (see Table 2 ).
6.Among the 21 pairs autosomes,the shape type of 17 pairs were metacentric (M),810 pairs were submetacentric (SM),1116 pairs were subtelocentric (ST) and 1721 pairs were acrocentric (T). In the 1 pair of sex chromosomes,the chromosome was submetacentric and the Y chromosome was metacentric. The chromsome karyotype of male rabbit was 44,Y.
7.Studeis were carried out to investigate the karyotyp e of Mya arenaria Linnaeus. Calculation from 105 cells showed that their ch romosome number(2n) was 34 on average and the foundermental number(NF) was 68. Relative lengths and arm ratios measured from 8 cells showed that the chromosom es could be classified into two groups: 12 pairs of metacentric chromosomes, 5 p airs of submetacentric chromosomes.
8.The number of diploid chromosome is 2n=36, FN=48 and the autosomes were divided into four groups:Group A consists of 5 pairs metacentric chromosome (Nos.1～5),Group B has 2 pairs of submetacentric (Nos.6～7),Group C has 8 pairs of acrocentric (Nos.8～15) and there are 2 small pairs of acrocentric in group D (Nos.16～17).
9.In L.awera, 11 hybridization sites were detected, 10 of which were at the end of short arm of all 10 acrocentric chromosomes. 1 site was detected near the centromere of metacentric chromosome, while the other homologous one had no hybridization signal. The results in L.awera demonstrated all 10 chromosome of type I were not telocentric but acrocentric chromosome.
10.The paper analyses the chromosome karyotype of Avena nuda L. It is a hexaploid and the number of chomosomes is 42. They are composed of 22 metacentric chromosomes, 18 submetacentric chromosomes and two subtelocentric chromosomes. There are six satellitic chromosomes of all. The karyotype formula is 2n=6x=42=22m+18sm(4SAT)+2st(2SAT).
