Modern Theory

The basics of contemporary theory explaining the mechanism of inheriting traits where created by Thomas Morgan and his coworkers. They studied genetics of fruit fly Drosophila melanogaster. According to this theory:

• traits are determined by genes that are transmitted from parents to children
• parent and children genes are identical
• genes are arranged in a line order on chromosomes
• each gene has it’s special place on chromosome – locus (pl loci)
• genes that lie on the same chromosome are united and are inherited together

Each man has 23 chromosomes from father and 23 from mother. Cytoplasmic DNA in inherited only from other, because only egg cell mitochondria are present in the zygote.