Table 3.

Chronology of Retrotransposon Insertion in the Mla Region

Elementa	Length of LTRb	Total Substitutionb	Base Substitution Ratec	Time (million years)d
BARE-1b	1813	15	0.0083	0.64
BARE-1c	1717	20	0.0116	0.89
Sabrina	1526	48	0.0315	2.42
BARE-1f	1817	22	0.0121	0.93
BARE-1d	1801	42	0.0233	1.79
BARE-1e	1761	47	0.0267	2.05
HORGY-1	286	27	0.0944	7.26
HORPIA-2	321	2	0.0062	0.48
HORPIA-3	521	14	0.0269	2.07

^aFull length retrotransposon with two LTRs.

^bDeletion or insertion was counted as a single event, including a retrotransposon insertion. The substitution was calculated as the total nucleotide difference between the two LTRs.

^cFor <10% base substitution rate, the rate was estimated as the number of substitutions per nucleotide (k) for calculation of divergence time.

^dDivergence time as calculated as k/2 × k_nus. k_nus designates the base substitution rate per nucleotide per year.