chapters 1-2
Post on 31-Dec-2015
28 Views
Preview:
DESCRIPTION
TRANSCRIPT
Overview• Mendel refuted the blending hypothesis, proposing
particulate units of inheritance - genes.• The idea of genetic inheritance gained support from the
behavior of chromosomes in meiosis and fertilization.• Linkage analysis can give information about the relative
location of genes on chromosomes.• The success of Mendelian genetics increased the importance
of characterizing the genetic material.• Chromosomes are composed of DNA and protein - the DNA
is the genetic material.• Nucleic acid structure gives important insight into genetic
function.
Review of Mendelian Inheritance
• Genes influence characters, and may occur in a number of different allelic forms.•Each organism / cell has two copies of each gene, and may be homozygous or heterozygous.•Gametes carry a single allele of each gene. Alleles are distributed randomly to gametes.•Fertilization combines the alleles present in the two participating gametes.
Linkage and Recombination• Linked genes are carried on the same chromosome.
• Homologous chromosomes exchange genetic material during synapsis. This changes the combinations of alleles that are possible
• Recombination frequency is proportional to physical distance.
•Genes are carried on chromosomes, and are inherited unchanged and undiluted.
•Mutations are rare events that change one allele to another.
•A genetic material that was inherited unchanged and undiluted, but subject to rare mutation answered a major flaw in evolutionary theory.
•The success of genetics intensified interest in the nature of the genetic material.
•Chromosomes are composed of DNA and Protein. Most biologists thought that Protein was the genetic material, while DNA was structural.
top related