1. **Stating the problem:** We are given a pedigree chart with genotypes labeled as RR, Rr, R_, and rr across four generations. The goal is to analyze the inheritance pattern and genotypes in the pedigree. 2. **Understanding genotypes and pedigree symbols:** - RR, Rr, R_, and rr represent genotypes where R is a dominant allele and r is recessive. - Filled symbols indicate affected individuals; unfilled symbols indicate unaffected. - Squares represent males; circles represent females; diamonds represent unknown sex. 3. **Analyzing Generation I:** - Individual I-1 is a filled circle labeled Rr (heterozygous affected female). - Individual I-2 is an unfilled square (unaffected male) with unknown genotype. 4. **Analyzing Generation II:** - II-1 is a filled circle labeled rr (homozygous recessive affected female). - II-2 is an unfilled square (unaffected male) with unknown genotype. - II-3 is an unfilled circle labeled RR (homozygous dominant unaffected female). - II-4 is a filled square labeled rr (homozygous recessive affected male). 5. **Analyzing Generation III:** - III-1 is a filled square (affected male) with unknown genotype. - III-2, III-3, III-4 are filled individuals labeled rr (affected homozygous recessive). - III-5 is an unfilled square (unaffected male) with unknown genotype. 6. **Analyzing Generation IV:** - IV-1 is a diamond (unknown sex) with unknown genotype. 7. **Inheritance pattern:** - The presence of affected individuals with rr genotype suggests a recessive trait. - Affected individuals are homozygous recessive (rr). - Unaffected individuals can be homozygous dominant (RR) or heterozygous carriers (Rr). 8. **Conclusion:** - The pedigree shows autosomal recessive inheritance. - Individuals with genotype rr are affected. - Carriers (Rr) are unaffected but can pass the recessive allele. This analysis helps understand the genetic transmission in the pedigree.