Fill in the Blanks Genetic variation reviewOnline version Complete this fill-in-the-blanks review for the topic of Genetic Variation by Belinda Schirmer 1 chromosome allele segregate diploid characteristic gamete alleles gene fertilisation two A is a segment of DNA on a that specifies a particular . It has two in an individual and or more alternative alleles in a population . An is an alternative form of the same gene and occurs in pairs in a individual . Alleles during formation and pair up during zygote formation ( ) , when the diploid condition of an organism is restored . 2 same homozygous genotypes physical heterozygous different phenotype 'Pure - breeding' refer to organisms that are ( e . g . , TT or tt ) for a particular trait i . e . have two of the alleles . 'Hybrid' genotypes are for a particular characteristic . That is , they have two alleles ( e . g . , Tt ) . Genotype is the genetic makeup of an organism and it determines the appearance , physiology and behaviour of an organism - or its . 3 frequencies quantative macroevolution allele genetics evolution Population combines Mendelian genetics and Darwinian to explain how changes in allele arise in populations and how these changes can lead to microevolution and . Population geneticists study mathmatical changes in gene and frequencies in populations to develop ways of exploring different evolutionary hypotheses . 4 SNP markers haplotype loci genome disease disorders chromosome single 1% SNPs are on chromosomes where alleles differ at a base . The rarer alleles must have a frequency of at least in a random set of individuals in a population to be termed a . SNPs are valuable as genetic for identifying individuals and can be associated with certain and traits . A is a cluster of marker alleles on the same and can be used for association studies in and to track the inheritance of different regions of the .