single gene inheritance and meiosis

a change in the nucleotide sequence of DNA creating alternative alleles of a gene

• the copies of each gene are separated from each other
• not every child rec eives the same combination of alleles
• it is the unique combination of maternal and paternal alleles that come together during fertilization that determines a person's genotype and contributes to his or her phenotype

• each parent is a diploid (2 copies of each chromosome) organism which produce specialized sex cells called gametes
• gametes are haploid (only one copy of each chromosome)
• sperm fertilizes the egg resulting in a diploid zygote
• zygote divides by mitotic cell division eventually generating enough cells to form a diploid baby

• specialized reproductive cells that carry one copy of each chromosome
• result of cell division called meiosis
• sperm are male gametes
• eggs are female gametes

• meiosis I
• meiosis II

• homologous chromosomes pair and line up next to one another in the middle of the cell
• the chromosomes of each homologous pair separate from one another and are divided into separate cells
• each daughter cell is haploid
• each chromosome is still in its replicated state

• sister chromatids separate, creating four haploid daughter cells
• each daughter cell will develop into egg or sperm

they inherit alleles from both parents and are genetically a combination of the 2

• recombination
• independent assortment

• when maternal and paternal chromosomes pair and physically exchange DNA segments
• as a result, maternal chromosomes actually contain segments (therefor alleles) from paternal chromosomes and vice versa
• 

• alleles of different genes are distributed independently of one another
• unique combination of maternal and paternal chromosomes is distributed into each sperm and each egg because possible combinations of alleles is very numerous (>8 million)
• maternal and paternal chromosomes separate according to how they have randomly lined up in the cell

having 2 different alleles

having 2 identical alleles

• the 2 copies of each chromosome in a diploid cell
• one chromosome from the mother and one from the father

the visible or measurable features of an individual

the particular genetic makeup of an individual

cell that is capable of developing into and adult organism

early stage of development reached when a zygote undergoes cell division ro form a multicellular structure

individual who is heterozygous for a particular gene of interest, and therefore can pass on the recessive allele without showing any of its effects