Course: Introduction to Biology — General Biology I (BIOL 101) · Silver Oak University (fictional sample) · Prof. Castellano
Module: Week 12 of 16 · Fall 2026 · in-person, two 75-minute lectures + one weekly lab
Objective covered: Objective 6 — Apply the principles of inheritance — extending Mendel to incomplete dominance, codominance, multiple alleles, sex linkage, and pedigrees — to predict genotypes, phenotypes, and probabilities.

This file holds two pieces: (A) the Module 12 Overview page ("Start Here") and (B) the Welcome Announcement that drips out when the module opens. Dates below assume a Tuesday/Thursday lecture pattern with Week 12 meeting Tue Nov 17 and Thu Nov 19, a lab that same week, and end-of-week work due Sunday Nov 22, 11:59 p.m. Adjust the day-of-week and times to match your section.

(A) Module 12 Overview — Start Here

Welcome to Week 12: Patterns of Inheritance

This is your home base for the week. Read it first, then work the checklist below from top to bottom. Everything you need is linked inside the module.

Last week, Mendel gave us the clean cases: one gene, two alleles, a dominant one that wins and a recessive one that hides, ratios like 3:1 and 9:3:3:1. This week we meet all the ways real inheritance is messier and more interesting. A red flower crossed with a white one can give pink offspring (the alleles blend). A person can show both the A and the B blood antigens at once (the alleles are co-expressed). A gene can ride on the X chromosome, which is why red-green colorblindness shows up far more often in men. And we'll learn to read a pedigree — a family tree of a trait — the way a genetic counselor does. The thread running through all of it is the same skill from Week 11: set up the cross, count the boxes, and turn the result into a probability.

The week's big question

"When inheritance breaks Mendel's simple rules — blending, co-expression, sex linkage — how do we still predict the odds for the next child?"

By Friday you'll be able to tell incomplete dominance from codominance, work an ABO blood-type cross, compute the chance a son is colorblind, and read a pedigree to decide whether a trait is dominant or recessive, autosomal or X-linked.

By the end of this week, you can…

Use this as a checklist. If you can do all four out loud, you're ready for the quiz.

• [ ] Distinguish incomplete dominance (a blend) from codominance (both alleles expressed) — and predict a cross for each (RW × RW → 1 red : 2 pink : 1 white, so P(pink) = 1/2).
• [ ] Work a multiple-allele ABO blood-type cross — type A (Iᴬi) × type B (Iᴮi) gives AB, A, B, and O each at 1/4, so P(type O) = 1/4.
• [ ] Predict sex-linked outcomes — a carrier mother (XᴬXᵃ) × an unaffected father (XᴬY) gives 1/2 of sons affected, 1/2 of daughters carriers, 0 daughters affected, and 1/4 of all children affected (all male).
• [ ] Read a pedigree — use the symbols to decide whether a trait is dominant or recessive and autosomal or X-linked.

What's due this week, and when

Work these in order — each one gets you ready for the next.

Heads-up on the AI tools: you'll use a chatbot to draft and explain, and then you judge its work against what we cover in class. Chatbots routinely mix up incomplete dominance and codominance, call a male a "carrier" of an X-linked recessive trait (he can't be — he's affected or not), or garble a blood-type ratio. Catching the model is the point — in the tutorial, the assignment, and the lab.

Late policy reminder: 10% off per day late. If life happens, reach out before the deadline — I'd much rather hear from you early.

How to succeed this week

• Lead with the idea, not the jargon. Incomplete dominance is just a blend (red + white = pink). Codominance is both showing at once (an AB blood type really has A and B). The terms come after the picture clicks.
• Memorize two tiny hooks. "Incomplete blends; co-dominance both shows." And "A son gets his only X from Mom — that's why X-linked traits run from mother to son."
• Draw the Punnett square every time. These problems are Week 11's machinery with new labels. Put the parent gametes on the edges, fill the four boxes, then count to get the probability.
• Probabilities are exact this week. RW × RW → 1/2 pink; A × B → 1/4 type O; carrier mom × unaffected dad → 1/2 of sons affected. These are not estimates — they fall out of the squares, and every one is pre-checked.
• Treat the chatbot as a smart intern, not an oracle. It drafts; you check. That habit is the whole semester in miniature — and these non-Mendelian patterns are exactly where AI slips.

You've already done the hard part in Week 11 — Punnett squares and probability. This week just adds new patterns on top of that foundation. Come to class ready to figure out how two brown-eyed-looking blood types can make a type-O baby. See you Tuesday.

(B) Welcome Announcement — Module 12

Release setting: post on the module's start day (offset = 0 days), i.e., Tue Nov 17, 2026 — not before. If your platform won't preserve the scheduled date on import, post this as a draft labeled "Release: Tue Nov 17."

Subject: Week 12 — can two parents make a type-O baby? 🩸

Hi everyone,

Quick puzzle before we start: a mother has type A blood and a father has type B blood. Can they have a child with type O blood? Most people say no — neither parent "has any O." But the answer is yes, and there's a one-in-four chance of it. By Friday you'll be able to prove it with a Punnett square.

This week — Patterns of Inheritance — we tackle the big question: When inheritance breaks Mendel's simple rules — blending, co-expression, sex linkage — how do we still predict the odds for the next child? We pick up exactly where Week 11 left off: same Punnett squares, same probability, new and more realistic patterns. You'll learn why a red-and-white cross can give pink, why an AB blood type shows both antigens at once, why red-green colorblindness is so much more common in men, and how to read a pedigree like a genetic counselor.

Three things not to miss:
1. Lecture Tutorial 12 — work through incomplete vs. codominance, ABO blood types, sex linkage, and pedigrees with one approved chatbot (Gemini, Claude, or ChatGPT) and submit the share link. You'll catch the model's mistakes — these patterns are where AI gets sloppy. Due Sun Nov 22.
2. Lab 12 ("Blood-Type & Pedigree Detective"), Quiz 12, Discussion 12, and Assignment 12 also close Sun Nov 22 — the lab is a virtual problem set where you compute the odds and then audit the AI's reading of a pedigree, so start early.
3. Open the Start Here page first — it lays out everything in order with due dates.

One promise: every probability this week is exact and pre-checked — 1/2 pink, 1/4 type O, 1/2 of sons colorblind. If you can draw the square and count the boxes, you can find the odds. That's the genetic-counselor move, and it's the heart of this module.

Bring your curiosity (and your Week-11 Punnett-square skills) to class on Tuesday.

See you soon,
Prof. Castellano