Transcript of "Human genetic inheritance patterns"
I. 5 Human Patterns of Inheritance:a. Complete Dominance (Basic Mendelian Genetics)b. Incomplete Dominancec. Co-dominanced. Sex-Linkede. Polygenic
a. Complete Dominance• Traits inherited are either DOMINANT or RECESSIVE• Ex. BB, Bb, bb
b. Incomplete Dominance• Traits inherited show a new phenotype that is a BLENDING or MIXING of parental alleles –HETEROZYGOUS results in a blending of two alleles –Use 2 different CAPITAL letters to represent (neither allele is dominant or recessive)
c. Co-dominance• Trait inherited shows a new phenotype that EXPRESSES BOTH parental alleles –HETEROZYGOUS condition results in the expression of both alleles – Use 2 different capital letters to represent
d. Sex Linked Traits• Traits are controlled by genes on the X or Y chromosomesa. _X linked traits can be passed on to males and femalesb. _Y linked traits can only be passed to males
X-Linked Traits1. Affect the X chromosome2. _FEMALES tend to be CARRIERS and XtY pass on the trait to their sons -3. Females can be affected but BOTH X chromosomes must have the gene for the trait - XtXt
e. Polygenic Traits• Traits are controlled by MULTIPLE gene pairs1.Genes may be on same or different chromosomes2.Expressed trait varies greatlyEx. Hair color, eye and skincolors, height, weight
II. How to study patterns of inheritance infamilies Two Methods: 1. _KARYOTYPE: Photograph of an individual’s chromosomes arranged in homologous pairs and can be viewed underneath a microscope a. Used to identify problems with chromosomes • _ABNORMAL NUMBERS • _DAMAGED OR BROKEN • _TO DETECT GENETIC DISEASES
Typical Karyotype: Normal Individual Pattern of Inheritance: Normal Chromosome Pattern Abnormality: None Notation: 46, XY, Male
2. _PEDIGREE CHART: Diagram to show genetic traits and used to map genetic traits through generationsa. Shows SEX, PHENOTYPE S, and GENOTYPES of family membersb. Can predict patterns of inheritancec. Uses symbols
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