ANTH 1001 Chapter : Ant3
Document Summary
Nondisjunction failure of chromosomes to separate 45 or 47 chromosomes in the gamete. Trisomy 21 nondisjunction of the e21st chromosome pair. No hysical symptoms except often tall, bad acne. Dominant traits are governed by an allele that can be expressed in the presence of another allele. For a recessive allele to be expressed, there must be two copies of the allele. When 2 copies of the same allele are present, the individual is homozygous. Principle of independent asortment: genes that code for different traits assort independently of each other during gamete formation, the genes controlling different traits are inherited indecently of one another in a process called random assortment. Genes that are located on the same chromosome usually remain together during meiosis. Traits controlled by alleles at one genetic locus. 1902 brachydactyly first mendelian trait identified in humans. Dominant alleles are more common because natural selection favors them. Alternative forms of genes account for variations in inherited characteristics alleles.
