180 likes | 358 Views
Sex-Linked Genes. Sample Problem!. Show, using a Punnett Square, that there is a 50% of having a boy or a girl when humans mate (aka get it on). Determination of Sex. Girls: XX (homologous sex chroms) Boys: XY (non-homol. sex chroms) Only ends of Y have regions homologous to X. X. Y.
E N D
Sample Problem! • Show, using a Punnett Square, that there is a 50% of having a boy or a girl when humans mate (aka get it on).
Determination of Sex • Girls: XX (homologous sex chroms) • Boys: XY (non-homol. sex chroms) • Only ends of Y have regions homologous to X X Y
Sex Linked Genes • Found on sex chroms, mainly X (contains more DNA). • Easy to spot b/c many males will have trait XY..if trait is on X, no competition on Y (less DNA)
Fruit Fly Genetics! • Good for genetic studies (Drosophila melanogaster: breed at a high rate A generation can be bred every 2 weeks Only have 4 pairs of chromosomes
Wild type = normal phenotype • Traits alternative to wild type: mutants
Some Traits are Sex Limited and Expression Depends on Sex of Individual