Deciphering neo-sex and B chromosome evolution by the draft genome of Drosophila albomicans

BMC Genomics

Table 2 Comparison of neo-sex chromosomes with other chromosomes

Chromosome	chrX (Muller A)	neo-sex (Muller C + D)	chr2 (Muller B + E)	chr4 (Muller F)^†
exonic SNP density *(♂/♀)	2.04/1.01(2.02)	4.61/0.97(4.75)	4.35/3.33(1.30)	0.18/0.01(18)
intronic SNPs density *(♂/♀)	2.58/0.77(3.35)	5.57/0.86(6.47)	5.84/2.75(2.12)	0.99/0.03(33)
putative pseudogenes No./total^#	11/2055	80/4751	54/5056	1/87
Ka average (× 10³)^§	1.03/0.42	2.02/0.58	1.89/1.26	0.73/0.16
Ka sd. (× 10³)	9.48/4.56	19.56/6.82	18.11/14.3	29.13/10.87
Tandem Duplications (%)^\|\|	13.8/5.6	20.7/5.5	15.3/3.79	14.9/5.8

* SNP density (sites/kb) was calculated using exon or intron regions of scaffolds mapping to the respective chromosomes, and shown as SNP density in male/SNP density in female, and their ratio in parentheses.
^# Male-specific putative pseudogenes were identified by premature stop codons, frameshifts or mutations at start codons. Shown are the pseudogene number/total mapped genes on each chromosome.
^§ Shown are nonsynonymous substitutions calculated in male/female. Sd.: standard deviation.
^|| Shown are proportions of tandem duplications among all the SV events for each chromosome identified in male/female.
^†Due to the low number of genes on chr4, inferences on this chromosome may be strongly affected by sampling effects.

ISSN: 1471-2164