Mendeloids Planning Form – Investigation 7

Eyebrows Bushy Smooth P1P1 F1F1 X All offspring have bushy eyebrows

Eyebrows Bushy METAPHASE OF MEIOSIS I TELOPHASE OF MEIOSIS I TELOPHASE OF MEIOSIS II Locus, Loci

Eyebrows Bushy BB METAPHASE OF MEIOSIS I TELOPHASE OF MEIOSIS I TELOPHASE OF MEIOSIS II B BBB B

Eyebrows METAPHASE OF MEIOSIS I TELOPHASE OF MEIOSIS I TELOPHASE OF MEIOSIS II b bbb b Smooth bb

Punnett Square bb B B Bb Possible gametes for the two parents Possible genotypes from these two parents bb = homozygous recessive BB = homozygous dominant Bb = offspring are heterozygous

Eyebrows Bushy is the dominant allele –B Smooth is caused by a recessive allele –b Monotypic gene – either bushy or smooth, no intermediate expressions Autosomal

Digits Number of toes – 2 or 3 –2 digit x 3 digit = all 2 digits –Which is dominant? –Is this trait monogenic or polygenic? –Sex-linked or autosomal?

Skin Color solid large spots medium spots small spots stippled

Skin Color Polygenic –AABB = solid –AABb or AaBB = large spots –AaBb or aaBB or AAbb = medium spots –Aabb or aaBb = small spots –aabb = stippled Autosomal

Hearing Dominant = normal hearing Recessive = deaf Sex-linked (= gene is present on the X chromosome but absent on the Y) –XX = female; XY = male X A X A X A X a X a X a X A Y X a Y