University:
The University Of Western Ontario
Course:
Biology 2290F | Scientific Method in Biology
Academic year:

2022
Views:

386

Pages:

3
Author:

Kyuwon J.

Monohybrid Cross ● Deals with alleles of one genes ● 3:1 ratio of phenotype Dihybrid Cross ● Independent assortment of alleles of 2 genes ● F1 generation crosses ○ 9:3:3:1 ratio phenotype of F2 Sex linked inheritance ● Allele carried on X or Y chromosomes ● Interested in looking for trait in X chromosome ● Could be X link dominant or recessive ○ X- linked dominant ■ Females will need one copy of mutant allele to have certain phenotype ○ X-linked recessive ■ 2 copies of mutant are needed to see actual change in phenotype ○ Male will receive phenotypical change even if theres only one copy of either dominant or recessive ■ Because male only have one X chromosome ● W+ is wildtype W is mutant White eye ● Therefore eye color is X-linked recessive Incomplete dominance ● Heterozygous phenotype ○ Blends two homozygous characteristic ○ RR X WW = RW ( pink) ■ Pink flower is intermediate between Red phenotype and white phenotype ○ None are fully dominant to each other ■ Partial expression happens at the same time ■ Phenotype ratio in F2 gen= 1:2:1(Red:Pink:White) Codominance ● Both alleles fully expressed in heterozygote ○ Both trait could be seen ○ Blood types ○ (A) x (B) = (AB) ■ AB blood expresses both A and B antigen phenotypes. Does not blends ○ No blending both allele are equally contributed ○ F2 gen ■ 1:2:1 (A::AB: B) Feature Incomplete Dominance Codominance Phenotype Blended intermediate Both traits visible Pink snapdragons (RW) AB blood type (AIB) Epistatisis ● Formation of non-mendelian genetics ● One gene could be capable for interfering with other expression ● 9:3:4 ratio could be seen in F2 generation ● B makes pigments ● E controls deposition ○ Must have both production and deposition of pigment for actual expression ○ 9:3:4 ratio has been proven