ANTHR 101 Lecture Notes - Lecture 5: Centromere, Dihybrid Cross, Zygosity
Document Summary
Somatic cells have 46 chromosomes in 23 homologous pairs. The complete chromosomal compliment of an individual height etc, but are the same size and shape. Locus- position on chromosome where gene/trait occurs. Homologous chromosomes- not identical, they don"t code for the same color, Two double stranded dna molecules are formed. 4 new daughter cells- 23 single stranded chromosomes in each gamete. Each gamete has half of the genetic material. Genotype- genetic make up of an organism. Dominant- masking the expression of another trait. Codominance: two alleles may be expressed in the phenotype. Genes occur in pairs because chromosomes occur in pairs. During gamete production, members of each gene pair separate so each gamete contains one member of a pair. During fertilization, the full number of chromosomes is restored. Shows us the possible genotypes in the next generation. Punnent squares also determine the expected proportion of phenotypes. Monohybrid (one trait) cross of two pea plants.
