Question About Plant Reproduction

David R. Hershey dh321 at PGSTUMAIL.PG.CC.MD.US
Sat Jan 13 00:49:59 EST 1996

The question was why can a plant reproduce with itself and not suffer the 
same harmful genetic mutations when animals interbreed.

First, it is not mutations but having two copies of a deleterious gene that
causes the problem when animals interbreed. Each parent contributes one
copy of each gene to its offspring. Closely related individuals are more
likely to have one copy of a recessive deleterious gene. Thus, they are
more likely to pass it along to their offspring. Normally
cross-pollinating plant species will usually suffer from inbreeding when
self-pollinated as well. Many plant species will not even set seed when
pollinated with their own pollen. Plant species often show hybrid vigor.
Many cultivated plants are hybrids, like hybrid corn. Plants that are
normally self-pollinating, like tomato, apparently have few deleterious
genes. They are considered to be homozygous because both copies of each
gene are the same. Cross-pollinating plants would be more heterozygous,
with different copies of some genes. 
David R. Hershey
Snail mail: 6700 Belcrest Road #112, Hyattsville, MD 20782-1398

Adjunct Professor, Biology/Horticulture Department
Prince George's Community College, Largo, MD 20772-2199

Email: dh321 at

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