BIO1011 Lecture Notes - Lecture 10: Thomas Hunt Morgan, Mitochondrion, Zygosity
6 Aug 2018
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Bio1011 lecture 10 patterns of inheritance 2. Found different results from reciprocal crosses: crosses where phenotypes of male and female parents reversed. Discovered by thomas hunt morgan, found white-eyed mutant of drosophila. X-linked recessive: males usually mostly affected transmitted through unaffected females (carriers) no male to male transmission. Supported by: behaviour of chromosomes at meiosis parallels me(cid:374)del"s laws. Sex-linked genes inheritance of a trait follows inheritance of a particular chromosome. Meiosis is the (cid:272)ellular (cid:271)asis for me(cid:374)del"s laws. The two alleles for a gene are carried on the two different homologous chromosomes. For traits controlled by single gene: alleles not completely dominant/recessive, more than two alleles single gene controls multiple phenotypes. For traits controlled by more than one gene: gene interaction many genes (polygenic) Mendel saw complete dominance in heterozygote only one allele expressed. Due to 50% gene product being enough for normal phenotype. Sometimes one allele not completely dominant over other:
